Prothrombin time is increased causes. prothrombin time

What it is? Prothrombin is a protein involved in the mechanism of blood coagulation, its synthesis occurs in the liver with the participation of vitamin K. Coagulation implies the transition of blood from a liquid state to a thick one.

For comfortable functioning in the body, blood must have a liquid consistency. If the vessels are damaged, the process of coagulation - thickening should occur. The body cannot lose a large volume of blood and clog the vessels with numerous blood clots.

• Laboratory analysis for prothrombin allows you to assess the quality of the coagulation mechanism.

Like any analysis, the prothrombin test is taken on an empty stomach. Patient who cannot perform this condition for health reasons, takes food 4-5 hours before the procedure.

Drugs that affect blood clotting should not be taken before taking the test - the results will be far from the truth.

If you cannot stop taking the medicine, tell your doctor that you are taking it.

An analysis of the quality of blood coagulation is necessary when the following diseases and suspicion of their presence:

• Antiphospholipid syndrome in pregnant women (it is manifested by miscarriages, missed pregnancy, placental insufficiency and other obstetric complications);
• Pathology of the liver;
• Atherosclerosis, varicose veins;
• Imbalance of vitamin K in the body;
• The presence of autoimmune diseases;
• Long-term use of anticoagulants indirect action.

A prothrombin test can also be prescribed for other diseases to screen for clotting. Under a microscope, the natural mechanism of blood clotting is recreated.

Potassium ions and thromboplastin are added to the recalcified plasma. The prothrombin complex has several coagulation factors - the analysis reveals a deficiency or surplus of such factors.

Prothrombin time - what is it? (norm)

Prothrombin time is the period of blood clotting from the moment a mixture of potassium and thromboplastin is added to the plasma. Thromboplastin used in laboratories has a certain level of sensitivity to factors II, V, VII and X.

The norm of prothrombin time is from 11 to 16 seconds, but the activity of the substance may differ depending on the sample. Accordingly, draw conclusions by comparing general meaning result in seconds is wrong. Relative evaluation required.

Prothrombin index - what is it? (norm)

The prothrombin index is the ratio of the fixed normal clotting time to the patient's individual indicator. More precisely, it allows you to determine prothrombin index analysis by INR (international normalized ratio).

The prothrombin index mathematically corrects the prothrombin time. Individual result in seconds divided by a fixed rate healthy person and multiplied by the sensitivity factor of the taken thromboplastin. The number of the latter is from 1 to 3, it can be found in the universal international classification.

Remember, when determining the prothrombin index: the norm for women and men is the same - from 0.8 to 1.3. But the figure may vary depending on age and health status.

The results of the preoperative study should not go beyond 0.85 - 1.25. An indicator of 3.0 - 4.0 is observed in a patient who had a heart attack myocardial or suffering from serious cardiovascular diseases.

The norm of the prothrombin index is 2.0 - 3.0 in the case of:

• Heart valve defects;
• Chronic atrial fibrillation and taking "Warfarin" against its background;
• Treatment of venous thrombosis and prevention of deep vessel thrombosis after surgery;
• Mitral and aortic valve implantation;
• Treatment of thromboembolism in the pulmonary artery.

The prothrombin index for INR above 6.0 requires urgent hospitalization of the patient. This coefficient indicates a high risk of internal bleeding in various locations.

The situation becomes more complicated if a person has already had ulcerative lesions. gastrointestinal tract, kidney failure, hypertension and disorders of blood flow in the brain. In this case, the potential risk of hemorrhagic (associated with bleeding) heart attacks in the organs increases.

Upon receipt of unsatisfactory results of the analysis according to the INR system, a second study is not required (the result is very sensitive and reliable). Index indicators do not differ depending on the type of laboratory material taken (capillary, venous blood).

• The prothrombin index is calculated taking into account the sensitivity of thromboplastin to blood coagulation factors.

Prothrombin according to Quick - what is it? (low, high and normal)

For several decades now, laboratory conditions calculate prothrombin according to Quick. What it is? This is the percentage of prothrombin activity. The scientist proposed to compare the indicator of the patient's prothrombin time with the indicator of the dependence of this period of time on the number of factors of the prothrombin complex in the taken plasma. The result is a percentage.

The construction of the dependence allows a very accurate assessment of the coagulation index, but the thromboplastin sensitivity coefficient is not taken into account.

This feature of the test affects the quality of the result in the region of critical values ​​below and above the norm. In standard results and minor deviations from them, the INR index and Quick index are directly proportional.

• The analysis results card in any laboratory will contain Quick prothrombin. The norm is in the range of 78% - 142%. The indicator may slightly exceed the average value, but at the same time it should be within normal percentages.

AT healthy body blood clotting is often increased - hypercoagulability is observed. Such a process is considered the norm until a person has any vascular diseases or chronic tissue damage. Their presence becomes a risk of blood clots.

After the appointment of blood-thinning drugs, regular screening is necessary. In some cases, a depot (a stage of accumulation of a substance) can form in the body from these funds, which will lead to a state of hypocoagulation with increased bleeding.

In addition, in the results of the analysis there may be an opposite process - hypercoagulation (increased coagulation activity). Indicators of insufficient blood density are observed much less frequently than excessive ones.

• However, any pathology of prothrombin factors needs to be controlled or even treated.

Elevated prothrombin in men and women

Prothrombin in men and women over 45-50 years of age is often elevated - more than 142% according to Quick. Hypercoagulability can be caused by both the presence of vascular disease and temporal factors. The latter include:

• An imbalance of vitamin K, which interferes with the proper synthesis of prothrombin in the liver, where it is normally formed;
• Chronic liver diseases and disorders of its work, which also interfere with the normal synthesis of prothrombin;
• Congenital anomalies: lack of factor II, V, VII, X blood clotting;
• The presence of a heparin inhibitor in the coagulation mechanism;
• Nephrotic syndrome, amyloidosis (deposition of a specific pathological protein in the organs);
• Taking antiseptic, laxatives, anabolic drugs, hormonal drugs, nicotine and acetylsalicylic acid, quinine, quinidine.

Elevated prothrombin, not due to the above factors, indicates the presence serious illnesses. So, diagnostic search is based on the following nosologies:

• Thromboembolism (clotting of blood vessels by blood clots);
• Polycythemia (an increase in the number of erythrocytes in the blood, including and in connection with oncological processes);
• cancers: leukemia, cancerous tumors different localization;
• Pre-infarction state of the body;
• Myocardial infarction.

Prothrombin in women may be elevated due to long-term use hormonal contraceptives, especially with an increased dosage of the estrogen component (from 30 to 50 mcg in 1 tablet).

If the patient has serious vascular disease, birth control pills should be discontinued. It is possible to switch to hormonal preparations local exposure (candles, vaginal ring).

Diet does not significantly affect blood clotting. You can reduce the Quick indicator by a few percent by adding “oxidizing” foods to the daily menu. An increased result causes a deficiency in the diet fermented milk products, red and black berries, citrus fruits, fatty fish and the amount of water drunk.

Low prothrombin - what does it mean?

Low prothrombin observed during hypocoagulation. This result indicates the tendency of the body to internal bleeding. The lack of coagulation factors is observed in the following situations:

• Vitamin K deficiency - a violation of the synthesis of prothrombin;
• Congenital deficiency of certain factors regulating processes in the blood;
• Pathologies of the liver that prevent the normal synthesis of coagulation factors;
• Lack of fibrinogen in the blood (congenital and acquired);
• Taking drugs that reduce the ability of blood to clot.

A low prothrombin rate indicates diseases:

• Dysbacteriosis;
• Pathology of the gastrointestinal tract;
• prothrombin deficiency;
• Hypovitaminosis.

Adjust slightly reduced rate prothrombin can be obtained with foods containing vitamin K. Cabbage, carrots, bananas, apples, pears, spinach and lettuce will be useful.

The reason for the lower results in the diet concerns more men than women. It is the male sex that prefers meat products to vegetables. As a result of such addictions, there is a deficiency of vitamins in the body.

prothrombin during pregnancy

Pregnant women are tested for prothrombin index in without fail. During childbirth, a low rate can lead to severe bleeding, and a high rate can lead to premature contractions and even a late miscarriage.

Therefore, it is very important to evaluate this indicator during gestation, especially if there are various complications both in this pregnancy and in the previous one.

During the gestation period, a blood test for the prothrombin index is taken at least 3 times (once per trimester). If future mother significant deviations are diagnosed, it is necessary to do a clotting test more often. The rate of prothrombin in the blood of women during pregnancy is lower than usual - from 70% to 120%.

Violations in the mechanism of blood clotting in pregnant women are evidenced by:

• Varicose veins on the limbs;
• Bleeding and appearance noticeable bruising after minor damage;
• Improper functioning of the liver;
• A long period of no results when trying to conceive;
• Conception through the IVF procedure;
• Multiple pregnancy;
• Delay in the development of the fetus from the norm;
• Drinking alcohol, smoking the expectant mother;
• Long-term treatment with anticoagulants;
• Multiple miscarriages.

Since prothrombin according to Quick decreases during pregnancy, the INR index also decreases. Changes are especially noticeable in the second trimester of gestation. Until the 13th week, the coefficient should correspond to the norm: from 0.8 to 1.3. Further, the indicator decreases:

1. From the 14th to the 20th week, the prothrombin index for INR ranges from 0.55 to 1.1;
2. From the 21st to the 28th week, the indicator can decrease to 0.5, but cannot exceed 1.15;
3. From the 29th to the 35th week, the result is 0.6 - 1.17;
4. From the 36th to the 42nd week, the index is from 0.55 to 1.15.

In the case of pregnant women, the INR indexing method is preferred. The indicators are quite low, and the Quick method gives errors at critical values.

Source: https://zdrav-lab.com/protrombin-norma/

Prothrombin: normal

AT human body there is a constant movement of blood - a life-giving fluid that provides nutrition to all cells of the body and metabolism. The length of the vessels is thousands of kilometers, and the area of ​​their location is more than half a hectare. It is impossible to imagine how all this is placed in the body of an adult.

But the amount of life-giving fluid is small: for men - a little more than five liters, and for women - about four.

Therefore, when injuries or cuts violate the integrity of the circulatory system, its contents can quickly splash out, threatening a person with a fatal outcome.

If blood loss is not prevented, the main transport link that nourishes the entire body will cease to exist.

To prevent this from happening, nature has created a system responsible for blood clotting. It is she who is able to launch protective mechanisms that close the wound and prevent blood from leaving the vessels.

The value of prothrombin in the body

Part of this system are special plasma proteins, which are called blood coagulation factors. They are marked with Roman numerals from I to XIII. Prothrombin is one of the main components. This protein is a blood coagulation factor II.

The name "prothrombin" suggests that it is the precursor of thrombin, the active enzyme. With its assistance, a clot (thrombus) is formed, closing the wound and stopping blood loss.

A normal level of prothrombin indicates that the blood clotting process is working efficiently and the body will be able to stop the loss of this life-giving fluid in time.

Protein testing is not as common as clinical blood testing. This procedure is not easy and is prescribed only in case of emergency, for example, in case of blood diseases or if there are problems with its coagulation.

Determination of the level of prothrombin - the most important test in the hemostasiogram.

Norm of prothrombin

Prothrombin molecules break down very easily and quickly. It is difficult to separate them from other proteins, which makes it difficult to determine its level. Several methods are used for qualitative analysis.

• Prothrombin according to Quick. Today this method is generally accepted and widespread. This technique provides for the calculation of the level of a substance as a percentage of allowable amount. The following values ​​are considered optimal (%):
  • minimum - 70;
  • the maximum is 120.

  The indicator allows you to determine the activity of the prothrombized plasma complex in comparison with various dilutions of the patient's plasma. A graph of the change in prothrombin is drawn up, the construction of which is based on data on the time of blood clotting.

  Experts consider the analysis according to Quick to be the most accurate when low prothrombin levels are recorded.

• Prothrombin index– is also defined as a percentage. The normal indicator is within the following limits (%):
  • minimum - 95;
  • the maximum is 105.

  The results of the two analyzes above may coincide if prothrombin is normal. But when its value is below the optimum, they diverge significantly. The index is highly dependent on the sensitivity of the chemicals used in the test.

• prothrombin time- shows how many seconds the plasma folds after adding a special mixture to it.

  The final test results depend on age. In newborn babies, blood clotting time can be from 14 to 18 seconds. And these figures are normal. In adults, a gap of 10 to 15 seconds is considered optimal.

• International Normalized Ratio - INR. This method is optional and is used to monitor the results of the prothrombin test.

  The results of such a test allow the doctor to control the effectiveness of treatment with anticoagulants - synthetic substances that reduce the content of prothrombin in the blood and slow down its clotting.

  These drugs are used in the treatment of thrombophlebitis, thrombosis, that is, diseases that form dangerous blood clots in venous vessels.

  The INR is normally 0.85–1.15.

  When treating diseases such as pulmonary embolism, venous thrombosis, or there are pathologies of the heart valves, the allowable limits increase to 3.0.

Indications for a prothrombin test

A blood test for prothrombin may be prescribed by a doctor in such cases:

• the patient has bleeding that does not stop for too long (this clearly indicates that blood clotting is below normal levels);
• the performance of liver enzymes and the liver as a whole is reduced;
• to monitor coagulation with prolonged use of anticoagulants;
• at antiphospholipid syndrome in order to clarify the cause of the disease;
• if there are diseases that are accompanied by a lack of vitamin K in the body.

Some indirect reasons requiring a prothrombin test are exclusively individual character. Most often, the study is assigned to the fair sex aged 50 to 60. It is at this time that hormonal changes occur, causing change in the composition and structure of the blood.

The following doctors can prescribe an analysis:

• therapist;
• traumatologist;
• surgeon;
• cardiologist;
• anesthesiologist-resuscitator;
• pulmonologist;
• pediatrician.

For research, blood from a vein is used. In order for the results to be as correct as possible, before the study, it is necessary to follow the standard rules:

• dinner no later than 8 pm, at least 12 hours before testing;
• before the study, be sure to put your nerves in order and not overstrain physically;
• do not smoke on the day of the test and do not take strong drinks.

As usual, blood is taken in the morning on an empty stomach. Medical staff should be informed of all medicines taken in the last day.

Prothrombin is elevated

An increased content of prothrombin in the blood indicates that blood clotting is more than normal. This means that it becomes too viscous, which impedes blood circulation and leads to blockage of blood vessels.

The following ailments can provoke an increase in the content of prothrombin, and hence blood clotting:

• malignant neoplasms;
• liver pathology;
• thromboembolism;
• polycythemia;
• progressive angina.

An increase in the amount of protein can also be caused by such factors:

• an excess of vitamin K in the body, with the help of which prothrombin is produced;
• use in the treatment of anticoagulants, antibiotics, nicotinic acid, hormonal contraceptives. Excessive use of aspirin, anabolics, laxatives can also affect the growth of prothrombin.

Quite often, the protein content increases during childbearing. Most often it manifests itself in the last trimester and does not need treatment.

Prothrombin is lowered: causes

A low level of prothrombin is dangerous because even a small injury that damages a blood vessel can result in significant blood loss. After all, the formation of a blood clot is slower than it should be.

A decrease in the level of prothrombin is provoked by such reasons:

• Individual pathologies of the liver, although most of them are accompanied by an increase in protein. The content of prothrombin decreases in acute and chronic forms hepatitis A. The same is true for cirrhosis of the liver.
• Insufficient synthesis of vitamin K by the body. This process develops most often due to gastrointestinal ailments and dysbacteriosis.
• Deficiency of fibrinogen - a protein that is produced in the liver and then converted into fibrin, which is the basis of a clot during blood clotting. Such a deficiency can be both congenital and acquired.
• Admission to medicinal purposes drugs that increase blood clotting.

It is possible to bring the level of prothrombin back to normal, but something should be done only after consulting a specialist.

Therapy is aimed at eliminating the ailments that caused the problem. Quite often, the basis of treatment is a special diet.

Source: http://OnWomen.ru/protrombin.html

Prothrombin (according to Quick) and prothrombin index, norm

An analysis for prothrombin is part of a blood coagulation study - a coagulogram.

In addition to the activity of this protein, indicators such as PI (prothrombin index, or PTI) and PT (prothrombin time) are also determined, which allow assessing the rate of clotting.

The normal values ​​of prothrombin in women, men and children, as well as the reasons for their deviation from the norm, are described in detail below.

Prothrombin - what is it?

Prothrombin is a high molecular weight protein compound involved in blood coagulation. Its production occurs in the liver in the presence of many substances. In particular, vitamin K, the deficiency of which leads to the synthesis of incorrect prothrombin molecules - they form blood clots that disrupt blood flow and can be fatal.

An analysis of prothrombin is needed to assess blood clotting, and the most accurate and versatile research method is PC - Quick prothrombin. What it is? This test detects the activity of prothrombin in the patient's blood compared to that in a control portion of plasma. This is the ratio of the clotting time of the patient's plasma to the time of this process in the sample.

The analysis is named after the scientist A. Quick, who proposed this method. In the test results, prothrombin according to Quick is expressed as a percentage. In the international nomenclature, it is assigned number II, since it was the second discovered after fibrinogen.

The Quick analysis is used not only to assess the activity of blood coagulation elements, but also to study the functioning of the gastrointestinal tract and liver. The PC test is more versatile than the prothrombin time and prothrombin index tests.

List of indications for the analysis of prothrombin according to Quick:

• impaired blood clotting;
• liver disease;
• antiphospholipid syndrome - increased thrombus formation due to autoimmune causes;
• blood cancer;
• pathologies in which the production of vitamin K is impaired (blockage biliary tract, poor digestibility of food in the intestines, etc.).

Reference: Vitamin K is produced by bacteria in the intestine and is actively involved in the formation of prothrombin. The rate of blood clotting is negatively affected by both its lack and excess.

The PC test is necessary to control the hemocoagulation system during the period of use of anticoagulants - Heparin, Warfarin and others. The structure of the blood and its composition also change with the onset of menopause in women (after 45 years), which is a risk factor for the development cancer. Therefore, at this age, it is especially important to regularly take an analysis for prothrombin.

Prothrombin time - what is it?

Depending on the causes of bleeding, blood can begin to clot in two ways - internal or external. The first is activated if the vessels are damaged from the outside - as a result of a bruise, cut, scratch, bite, abrasion. The internal pathway works when the integrity of the blood vessel wall has been compromised from within - under the influence of toxins, pathogenic microorganisms, antibodies.

Prothrombin time is an indicator that reflects the work of the internal pathway in the hemocoagulation system.

It reflects the effectiveness of the "repair" of vessels that have been damaged by compounds circulating in the bloodstream. In the results of the analysis, the prothrombin time may be referred to as PT, ecombipl RT or RT.

Prothrombin time is increased, compared with the norm, under the following conditions:

• lack of vitamin K;
• the initial stage of DIC;
• liver pathologies;
• taking drugs from the group of anticoagulants - Tromboass, Agregal, Warfarin, Heparin and others;
• hemorrhagic diathesis of newborns;
• inflammation and blockage of the biliary tract;
• Zollinger-Ellison syndrome;
• malabsorption of fats in the intestine;
• deficiency of coagulation factors - fibrinogen, prothrombin, AC-globulin, proconvertin and Stuart-Prauer factor.

The lower the concentration of prothrombin in the blood, the higher the prothrombin time, because the process of blood clotting is slower.

prothrombin time is decreased if the following conditions exist:

• pregnancy;
• DIC;
• high levels of antithrombin-III and other anticoagulants produced by the body;
• deviation from the norm of hematocrit - the ratio of the volume of blood cells to the volume of plasma.

The low prothrombin time during the test may be due to the long storage of plasma before the study and irregularities in blood sampling.

Prothrombin index

The prothrombin index is an indicator that reflects the rate at which blood coagulation starts along the internal pathway. It is calculated on the basis of prothrombin time, so its increase is observed with the same disorders in the body as an increase in PT, as well as a decrease.

To determine the PTI, the patient's plasma clotting time is divided by this value in the control sample. Normally, the result should be 95-105%.

The accuracy of the analysis for the prothrombin index depends on the sensitivity of the drugs used in the laboratory. Therefore, it cannot be called universal, in contrast to the Quick prothrombin test.

Elevated prothrombin

If the Quick prothrombin test is elevated and shows high values ​​​​(up to 150% or more), the reason for this may be:

• DIC syndrome;
• cholestasis and other diseases that reduce the activity of vitamin K;
• diseases that disrupt the functioning of fibrin;
• hereditary and acquired pathologies leading to a deficiency of coagulation factors (amyloidosis, liver disease, nephrotic syndrome).

Elevated prothrombin also appears with long-term use drugs:

• antibiotics;
• diuretics;
• aspirin;
• indirect anticoagulants;
• anabolics;
• Methotrexate;
• laxatives;
• nicotinic acid;
• Heparin and other clotting inhibitors.

Prothrombin rate, table

The extreme values ​​of the PC are the numbers below 78 and above 142%. The rates of prothrombin according to Quick are presented in the table.

Norms of prothrombin in men and women of one age group do not differ. Normal prothrombin time for both sexes is 9-12 sec. The rate of prothrombin in the blood of women who are expecting a baby is slightly higher than normal values.

Low prothrombin

Low prothrombin according to Quick always indicates an excessively rapid formation of blood clots and can be triggered by conditions such as:

• pregnancy and the period after childbirth;
• vein thrombosis;
• penetration of thromboplastin into the vessels due to tissue damage;
• high blood viscosity (polycythemia).

The decrease in PC can be explained by such a dependence - the activity of the prothrombin protein is high, the blood coagulates faster compared to the control plasma sample, therefore the Quick prothrombin test is below normal.

Low prothrombin according to Quick can also be caused by taking Mercaptopurine, hormonal contraceptives, and other drugs that increase blood density.

prothrombin during pregnancy

A coagulogram is an obligatory part of the tests for pregnant women. The evaluation of this study, including prothrombin tests, allows timely detection of conditions dangerous to the health of the child and the expectant mother.

Prothrombin according to Quick during pregnancy is normally slightly lowered, that is, the activity of the coagulation system increases. This is due to the emergence of a new circle of blood circulation and the preparation of the body for the upcoming birth and possible blood loss.

A very low PC can provoke the development of thrombosis, and its increase in pregnant women can cause heavy bleeding during childbirth, including internal.

Severe bleeding with incompatibility of the Rh factor of the woman and the fetus can cause hemolytic shock due to the mixing of the blood of mother and child. This is one of common causes postpartum mortality.

To avoid this, in this situation, not only monitor and control the state of the coagulation system, but also introduce immunoglobulins at the 28th week of pregnancy that destroy potentially dangerous antibodies.

• The norm of the prothrombin index for women carrying a child is 80-100%. At its high values, in order to avoid thrombosis and other complications, drugs are indicated that reduce the increased activity of coagulation.
• Low PI, on the contrary, carries the risk of bleeding. The normal value of prothrombin time for pregnant women is 11-18 seconds. During pregnancy, any deviation from the norm in the coagulogram is a reason for a thorough examination and, in most cases, hospitalization.

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Source: http://medknsltant.com/prothrombin/

prothrombin is normal

It is very difficult for a person who is far from medicine to assess what a blood test that is completely incomprehensible at first glance can tell a specialist. In fact, each indicator allows you to get a fairly large amount of useful information.

For example, prothrombin is vital important protein. Checking the compliance of prothrombin with the norm is not carried out as often as, for example, general analysis blood.

This is a rather complicated study, therefore it is prescribed in special cases: for screening studies, blood diseases, clotting problems.

What is the norm of prothrombin in the blood?

There are several different tests for prothrombin:

1. Prothrombin according to Quick allows you to determine the level of protein activity.
2. Knowing the prothrombin time, you can determine how many seconds the patient's blood coagulates.
3. The prothrombin index, or PTI for short, is the ratio of the normal prothrombin time to the parameters of the patient being examined.
4. INR - international normalized ratio - an indicator opposite to IPT. It shows the ratio of the patient's prothrombin time to the normal value of prothrombin.

The most informative and effective are studies that determine the prothrombin index and prothrombin according to Quick:

1. The normal value of prothrombin in the blood according to Quick is in the range from 78 to 142 percent.
2. The PTI value may vary depending on the sensitivity of the reagents used for the study, but ideally should be 95-105%.

For both men and women, the prothrombin rate remains the same. Any deviation from the norm is cause for concern. Can increase or decrease prothrombin levels various diseases, some of which are serious threat for good health.

What causes the level of prothrombin in the blood to be higher than normal?

Too much prothrombin in the blood is a symptom of increased blood clotting. This can be caused by the following factors:

1. The production of prothrombin is associated with vitamin K. Increased amount This protein in the blood indicates an overabundance of the vitamin.
2. A large amount of prothrombin can be observed in malignant tumors.
3. An excess of the norm in the blood test for prothrombin is observed in patients in a pre-infarction state.
4. It is very common for protein levels to spike during pregnancy. Especially in the later stages.
5. Prothrombin can also increase in patients suffering from liver problems.
6. Sometimes excess protein occurs due to the use of Aspirin, hormonal contraceptives, diuretics, corticosteroids, anabolics, laxatives.
7. Thromboembolism and polycythemia cause an increase in prothrombin.

Why is prothrombin below normal?

A decrease in prothrombin on the state of health also does not affect very well. Cause it such reasons:

1. Some liver diseases contribute to an increase in prothrombin, but in acute and chronic forms of hepatitis or cirrhosis, the protein decreases.
2. An analysis for prothrombin will show a value below normal if the patient is taking drugs that increase clotting.
3. The level of prothrombin decreases with a deficiency of vitamin K. Most often, the problem develops against the background of dysbacteriosis and diseases of the gastrointestinal tract.
4. The lack of fibrinogen negatively affects the test results. Moreover, the deficiency can be congenital or acquired.

It is possible to normalize the level of prothrombin, but it is better to coordinate the methods of treatment with a specialist. Treatment course depends on the cause of the problem. In most cases, the patient is offered special diet. Often, special preparations are required for recovery.

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Laboratory measurement

Normal value

The normal indicator of prothrombin time is 11-16 seconds, for INR - 0.8-1.2. Oral anticoagulant therapy (warfarin) requires a higher target INR level - usually in the range of 2-3.

Methodology

When determining prothrombin time, blood plasma is most often used. Blood is drawn into a tube containing sodium citrate, which acts as an anticoagulant by binding calcium in the blood sample. The blood is gently mixed, then centrifuged to separate the blood cells from the plasma. In newborns, whole blood is used for analysis. Further analysis is performed automatically at a temperature of 37 ° C. Excess calcium is added to the plasma sample (thus neutralizing the effect of citrate), which restores the ability of the plasma to clot. For an accurate measurement, the proportion of blood and citrate in the tube must be fixed (usually a ratio of 9:1 is used). Many labs will refuse to test if the tube is not completely filled with blood - and thus contains a relatively large amount of citrate. Next, tissue factor (also known as coagulation factor III) is added to the plasma with calcium and the time to clot formation is recorded, which is determined by optical measurement. Some laboratories use mechanical determination of the moment of clot formation, which allows more accurate determination of PTP in the case of a large number of fat droplets in plasma and in hyperbilirubinemia.

Prothrombin index

It is calculated as the ratio of the PTT of the control plasma to the PTT of the studied patient's plasma, expressed as a percentage.

International normalized ratio

The results of prothrombin time in healthy individuals vary depending on the type of tissue factor reagent (thromboplastin) used in different laboratories. The INR indicator was introduced in clinical practice to standardize PTV test results. Manufacturers of the reagent (tissue factor) for the PTP test are required to indicate the MIC (International Sensitivity Index) for the reagents. MIC shows tissue factor activity in a given batch of reagent produced, compared to a standardized sample. The MIC value is usually between 1.0 and 2.0. The INR is calculated as the ratio of the patient's PTT to the normal PTT raised to the MIC value of the reagent used in the test. INR \u003d (PTV of the patient / PTV norm) MIC

Interpretation

Prothrombin time is the time for clot formation after tissue factor is added to the plasma (the reagent is obtained from animal tissues). This indicator allows you to evaluate the external and general ways of blood coagulation. The rate of blood coagulation along the external pathway is highly dependent on the concentration of coagulation factor VII. Factor VII - a protein with a short lifespan, vitamin K is necessary for its synthesis. PTT can be prolonged as a result of vitamin K deficiency that occurs with the use of warfarin (desirable clinical effect), with maladsorption syndrome, with insufficient bacterial colonization of the intestine (for example, in newborns) . In addition, an insufficient concentration of factor VII can be observed in liver diseases (impaired synthesis), or increased consumption of factor (DIC), which also prolongs the PTT. At INR above 5.0 - observed high risk bleeding, with INR below 0.5 - a high risk of thrombosis. Normal INR values ​​in healthy individuals are from 0.8 to 1.3. With warfarin therapy, the target INR level is 2.0-3.0, although in some cases, for example, in the presence of an artificial mechanical heart valve, a higher target INR level may be required in the perioperative period.

State	PTV	APTT	Bleeding time	platelets
vitamin K deficiency or warfarin therapy	lengthened	lengthened	Without changes	Without changes
DIC	lengthened	Elongated shortened or normal	lengthened	Reduced
von Willebrand disease	Not changed	lengthened	lengthened	Not changed
Hemophilia	Not changed	lengthened	Not changed	Not changed
Aspirin therapy	Not changed	Not changed	lengthened	Not changed
Thrombocytopenia	Not changed	Not changed	lengthened	Reduced
Liver failure (early stage)	lengthened	Not changed	Not changed	Not changed
Liver failure (late stage)	lengthened	lengthened	lengthened	Reduced
Uremia	Not changed	Not changed	lengthened	Not changed
Congenital afibirinogenemia	lengthened	lengthened	lengthened	Not changed
Factor V deficiency	lengthened	lengthened	Not changed	Not changed
Factor X deficiency	lengthened	lengthened	Not changed	Not changed

Factors Affecting Accuracy

Lupus anticoagulant, a circulating inhibitor that predisposes to thrombosis, affects PTT results depending on the technique used. Variations in the activity of the reagent (tissue factor) lead to a decrease in the accuracy of the INR, despite attempts international standardization PTT (introduction of INR) in 2005, there were still significant differences in the indicators determined in different laboratories.

Statistics

Approximately 800 million INR/PTT tests are performed annually worldwide.

Express Definition

Except laboratory method determination of INR described above, the rapid method that allows you to monitor INR at home is becoming increasingly popular. The new generation of devices and reagents for rapid tests allow you to get results close to laboratory accuracy. Typically, portable devices are used at home, such as Roche Coaguchek S or HemoSense INRatio.

see also

• Thrombin generation test (thrombin potential, endogenous thrombin potential)
• Activated partial thromboplastin time (APTT)

Notes

Wikimedia Foundation. 2010 .

See what "Prothrombin time" is in other dictionaries:

- (syn. Quick time) an indicator of the intensity of blood coagulation processes at the stage of conversion of prothrombin to thrombin, which is the duration (in seconds) of the formation of a clot of the studied blood plasma in the presence of thromboplastin and ... ... Big medical dictionary

The time required for blood to clot after adding calcium and thromboplastin to the test blood sample. A large prothrombin time (compared to the control sample) indicates the presence in the body of a deficiency of coagulating ... ... medical terms

PROTHROMBIN TIME- (prothrombin time (PT)) the time required for blood clotting after adding calcium and thromboplastin to the test blood sample. A large prothrombin time (compared to the control sample) indicates the presence in the body of ... ... Dictionary in medicine

- (A. J. Quick, born in 1894, American doctor) see Prothrombin time ... Big Medical Dictionary

- (Greek haimorrhagia bleeding) a group of diseases and pathological conditions of a hereditary or acquired nature, the common manifestation of which is a hemorrhagic syndrome (a tendency to recurrent intense long-term, most often ... ... Medical Encyclopedia

- ... Wikipedia

Active ingredient ›› Fluconazole* (Fluconazole*) Latin name Diflucan ATX: ›› J02AC01 Fluconazole Pharmacological group: Antifungals Nosological classification (ICD 10) ›› B20.4 HIV disease with manifestations of ... ... Medicine Dictionary

I Anticoagulants (anticoagulantia; Greek anti against + Latin coagulans, coagulantis causing clotting) drugs that reduce blood clotting by inhibiting the formation of fibrin. There are A. direct and indirect action. ... ... Medical Encyclopedia

Article instruction. The text of this article almost completely repeats the instructions for use of the medicinal product provided by its manufacturer. This violates the rule about the inadmissibility of instructions in encyclopedia articles. In addition ... Wikipedia

Warfarin is a drug, an indirect anticoagulant. Content 1 international name 2 Trade names 3 Dosage form... Wikipedia

Quite often, with special laboratory tests, it is found that the patient is elevated. What can such a change indicate? How dangerous is this condition? Why is it necessary to determine the prothrombin time, and to whom are these tests indicated? These questions are of interest to many.

What is prothrombin time?

It's no secret that the processes of blood coagulation are extremely important for the normal functioning of the human body. In addition, the blood contains specific factors that prevent increased clotting, thereby preventing the formation of blood clots and blockage of blood vessels. The balance in the work of these two sections ensures the normal functioning of all organ systems.

In order to understand what is prothrombin time, you need to consider general mechanism coagulation. Damage to the vascular wall causes activation special complex enzymes that provide the formation of fibrin filaments. In turn, these threads become a strong framework for a blood clot, which. The blood coagulation system can be triggered in two ways - when the outer or inner layers of the vessel are damaged.

Thus, prothrombin time helps to find out how fast the blood coagulation system works when externally activated.

Prothrombin time, INR and prothrombin index - what is it?

Naturally, the speed when damaged outer layers vascular wall is not an absolute indicator. By the way, the PV should normally be from 11 to 16 seconds, and in order to obtain accurate data on the functioning of the body, additional tests are needed.

AT modern medicine international normalized ratio or INR is used. In such a study, the patient's prothrombin time is compared with the same indicator of plasma normalized according to international standards. The formula looks like in the following way: Patient PV/Normalized plasma PV (the result is raised to the power of the so-called International Thromboplastin Sensitivity Index).

The prothrombin index also determines the ratio of the PV of the control plasma to the PT of the patient's plasma, but as a percentage. By the way, the normal index should be 95 - 100%.

Today is the most exact test. This study helps to compare the activity of the patient's prothrombin complex with that of the control plasma.

Indications for research

In fact, there are many diseases and disorders that affect the process. That is why such a study is carried out quite often. For example, it is prescribed to patients with suspected thrombosis. The analysis is also indicated if the patient has numerous hematomas and hemorrhages of unknown origin.

The same study is used along with some other procedures in order to evaluate the work of the liver. If you suspect a deficiency or metabolic disorders of vitamin K, patients are also sent for analysis. Prothrombin and in pregnant women, since this period of life is associated with some risks.

How are samples taken?

In order to determine the prothrombin time, fresh plasma is needed. First, blood is taken from the patient. By the way, in this case, samples are taken from a vein, placed in a test tube with sodium citrate, which binds calcium ions.

In fact, no special preparation for testing is required. Blood is taken on an empty stomach, so in most laboratories, blood is taken in morning time(up to 11 hours). Most likely, you will receive the results of the tests the next day. It is also worth noting that some factors can distort the results, so be sure to consult a doctor before testing.

How is prothrombin time determined in the laboratory?

Determination of prothrombin time is a relatively simple procedure. As already mentioned, after sampling, the blood is mixed with potassium citrate and delivered to the laboratory. Next, the sample is mixed and placed in a centrifuge at a temperature of 37 o C. After that, the required amount of calcium is added to the sample, and then tissue blood. Then note the time during which the thrombus is formed. As already mentioned, it should be 11-16 seconds.

Increasing performance

If the prothrombin time is increased, is it dangerous? Unfortunately, test results do not always match normal value. What disorders cause increased prothrombin time?

• There are some congenital diseases accompanied by a deficiency of blood clotting factors.
• In some cases an insufficient amount clotting factors is acquired. In particular, a similar condition is observed in a number of autoimmune diseases and amyloidosis.
• A similar change in PV is observed in diseases of the liver and liver failure.
• DIC may also be the cause.
• With developing hypovitaminosis K, prothrombin time is also increased. In turn, a deficiency of this vitamin can be observed in dysbacteriosis, malabsorption syndrome, as well as some diseases of the gallbladder and pancreas.
• The intake of certain anticoagulants leads to an increase in PV.
• Massive blood transfusion can also affect the results of the study.

If the score is down

In some patients, the prothrombin time is reduced - thrombus ( blood clot) is formed much faster than required. This is also a dangerous condition that is fraught with the development of blockage of blood vessels.

Quite often, a decrease in PV indicates the presence or risk of developing thrombosis, which is extremely dangerous, since it is often a threat to the patient's life. A decrease in the indicator is often associated with the intake of certain groups of hormonal contraceptives. It can also be caused by polycythemia. In pregnant women, blood clots much faster in the third trimester of pregnancy.

What can affect the reliability of the analyzes?

It is immediately worth noting that there are many factors that, to one degree or another, can affect the result of the analysis. As already mentioned, taking anticoagulants and some hormonal drugs may increase the duration of thrombus formation. But there are some other limitations as well.

In particular, the results of the study will be false if you are taking aspirin, barbiturates, medicines containing vitamin K. In addition, some groups of antibiotics also affect the prothrombin time.

Digestive problems can also affect test results. In particular, persistent diarrhea or frequent vomiting lead to dehydration. In addition, with such disorders, the absorption of vitamins and minerals, including tocopherol (vitamin K), is disrupted.

If you eat foods that are high in vitamin K, the test results may not be accurate. A few days before the analysis, limit the amount of pork and beef liver, soy products, peas, green tea, cabbage, herbs and broccoli.

The process of blood clotting is also affected by alcohol abuse, so, again, a few days before testing, alcohol should be avoided.

Factors that affect PT include taking laxatives and some homeopathic medicines.

If you are taking any medications, be sure to tell your doctor. Tell the specialist about the features of your diet and the health problems present. Otherwise, the analysis will not be informative, and the doctor may prescribe completely inappropriate drugs.

Why determine the prothrombin time for a pregnant woman?

It's no secret that during the bearing of a child, a woman's body (especially the circulatory and endocrine system) undergoes significant changes. That is why it is extremely important to determine the prothrombin time during pregnancy.

In some women, blood clotting increases during this period, which leads to thrombosis and blockage of blood vessels, carrying blood to the child's body. With absence timely treatment similar violation can lead to DIC and even fetal death.

On the other hand, during pregnancy, the blood may thin too much. In such cases there is big risk massive blood loss, especially during childbirth. Determining the prothrombin time allows the doctor to identify a particular disorder in time and prevent the development of complications.

Prothrombin, prothrombin index and time: blood norms, decoding of analyzes

Typically, doing hospital treatment, each patient the next morning before breakfast delivers mandatory tests from a finger (general blood test, sugar and prothrombin). These laboratory tests are referred to as the main indicative studies, since they are the ones that “draw” big picture the patient's condition. The rest (biochemical, including coagulation) tests can be prescribed on the day of admission, if the problem in the patient's body is clearly defined, or if, during the examination and treatment, the goal is to thoroughly study the functional abilities of the patient's organs and systems and monitor the effectiveness of therapy .

Unique environment moving around blood vessels, according to its characteristics attributed to the connective tissue. Being in a liquid state and possessing fluidity, which prevents the bonding of shaped elements, blood, however, is able to quickly clot when the vascular wall is damaged. She has such an opportunity thanks to the blood coagulation system and its factor, one of which is prothrombin . It should be noted that all factors without violating the integrity of the vascular walls are in an inactive state. Activation of factors and the formation of blood clots inside the circulatory system for no reason threatens with serious complications for the body.

What is prothrombin?

stages of blood clotting

Prothrombin or factor II (FII) of the prothrombin complex is a protein (glycoprotein), a plasma factor of the coagulation system, which belongs to alpha2-globulins and is synthesized by hepatocytes (liver cells). It is important to note that prothrombin production it will be noticeably difficult if the amount of vitamin K in the body for some reason decreases, which the synthesis so needs this factor. If everything is normal in the body, then prothrombin does not show any activity, remaining as a precursor of thrombin, an enzyme that causes polymerization and the formation of a clot (thrombus), if necessary.

In circulating blood, plasma factors, being in the form of an inactive form of a profactor (prothrombin → thrombin), always remain in relatively constant concentrations, activation occurs under the influence of coagulation factor XII ( internal system hemostasis) and in contact of blood with damaged tissues(external hemostasis system).

The norm of prothrombin in the blood in healthy people is 0.10 - 0.15 g / l (1.4 - 2.1 μmol / l).

Importance of the prothrombin complex

The lack of this factor can be both congenital and educated in the process of life. Congenital prothrombin deficiency is not so common, that is, it refers to a rare pathology. Low prothrombin from birth is due to a mutation of recessive genes located on chromosome 11.

With hypoproteinemia of any origin, as a rule, the level of this protein is also reduced. The liver affected by the disease (hepatocytes are the site of formation of the main factors of the prothrombin complex) and K-avitaminosis (vitamin K is involved in the synthesis of FII and other factors that are called K-dependent) give a sharp drop in the concentration of this indicator.

Decreased levels of prothrombin lead to the fact that it takes more time for blood to clot. To determine how the coagulation system works depending on the level of prothrombin, coagulation tests are used in clinical laboratory diagnostics, which allow you to have an idea of ​​the state of the entire prothrombin complex:

• PTI (prothrombin index, in percent);
• PO (prothrombin ratio, inverse PTI value, in percent);
• PTT (prothrombin time, in seconds);
• Prothrombin according to Quick (more sensitive analysis than PTI and PTT, as a percentage);
• INR (international normalized ratio, in percent).

Excessive activity of prothrombin without any need is also fraught with various troubles, and, at times, a disaster for the body. Increased clotting, the formation of clots that can close a vital blood vessel, can result in dangerous situation up to and including death.

Orientation tests and full analysis

The study of blood coagulation, as a rule, begins with indicative methods that make it possible to detect an anomaly of coagulation (prothrombin) without revealing its essence. Then, based on the results of the analysis of the coagulation ability of the blood, other (already specific) methods are prescribed (PTT, INR, APTT and other indicators of the hemostasiogram).

As for the prothrombin test, it is a very important component and can be presented in various forms. The lack of factors of the prothrombin complex (II, V, VII, X) is determined mainly in the analysis of PTT according to Quick, which primarily reveals a violation of the external formation of thromboplastin. However, it is also possible to study these indicators separately according to the principle of replacement samples.

Meanwhile, it is impossible to ignore the indicators of the coagulation ability of blood in women during the planning period or the onset of pregnancy, because this allows you to calculate possible risks during childbirth. Bearing in mind these indicators during pregnancy, it is possible to foresee and prevent bleeding (if the PTV is prolonged) or the development of thrombosis and premature detachment of the placenta, if the blood shows a particularly high tendency to clot. During the very period of childbirth, the prothrombin time is somewhat shortened compared to the norm, and the prothrombin index is increased. In women during pregnancy and childbirth, the study of the coagulation function of the blood is not enough only with indicators of the prothrombin complex. In order to have a complete picture of the functional ability of the hemostasis system, expectant mothers are prescribed a maximum of coagulogram indicators.

prothrombin time

prothrombin time as laboratory test, enables clinicians to quickly assess not only the external hemostasis system, but the entire cascade of blood coagulation reactions.

In emergency situations for the body (injuries with tissue damage, heavy bleeding, necrosis and other pathological conditions), a glycoprotein enters the blood, a membrane protein - tissue thromboplastin, which indicates the inclusion of a reserve (external) hemostasis system.

Tissue (cellular) thromboplastin, called tissue factor (TF), interacting with coagulation factors (FVII) circulating in the bloodstream, successively includes other plasma thromboplastic factors in the process. This means that the hemocoagulation system is activated and the first phase of coagulation begins - the transformation of inactive prothrombin into active thrombin. Thrombin causes the enzymatic conversion of fibrinogen into fibrin, under its influence factors (V, VIII, IX, XIII) are activated, it destroys platelets, which causes (together with Ca ++) viscous metamorphosis platelets, promoting the release of platelet factors.

The norm of PTT in adults ranges from 11-15 seconds (in newborns up to 3-4 days of life - 12-18, in premature babies - 15-20). In newborn full-term infants from 4-5 days of life, the prothrombin time corresponds to that of an adult.

This indicator is increased (clotting time is lengthened) in the following pathological conditions:

1. Diseases of the liver, because there is a synthesis of prothrombin;
2. Lack of vitamin K, the participation of which is necessary for the synthesis of K-dependent factors (including prothrombin);
3. Increasing the level blocking thrombin and other factors of the hemocoagulation system;
4. Increasing the fibrinolytic ability of the blood (dissolution of clots);
5. pancreatic cancer;
6. Separate hematological pathology (myeloid metaplasia);
7. GrBN ( hemorrhagic disease newborns);
8. High level of erythrocytes in the blood (above 6.0 x 10 12 / l);

Whole blood taken with an anticoagulant (sodium citrate) serves as a biological material for the study of prothrombin time using the one-stage method according to Quick (as the analysis is called).

PTT, Quick test or thromboplastin time is an indicator of the external factor II activation system, where prothrombin time depends on the concentration of fibrinogen in the blood plasma, factors V, VII, X. The PTT norm (Quick test) is determined thromboplastin activity and is 12-20 seconds.

Prothrombin according to Quick

The definition of "prothrombin according to Quick" means the concentration of factors of the prothrombin complex as a percentage of the norm. This method is currently one of the most meaningful ways prothrombin studies.

The test allows you to identify the activity of the factors of the prothrombin complex of the patient's blood when compared with the known PTT of "normal" plasma. This method is undoubtedly more informative than the calculation of PTI. Quick prothrombin determines FII in a patient based on a calibration graph ( dependence of PTT on the total, total, activity of all participants in the reaction - factors of the prothrombin complex of diluted "healthy" plasma).

Normal prothrombin values ​​according to Quick vary more widely than PTI, and normally range from 75 to 140%. Among women upper bounds standards are usually lower. The results of the analysis may depend on the age of the patient, the treatment that he takes (anticoagulants), the sensitivity of the reacting substances.

Prothrombin according to Quick is primarily reduced during treatment with indirect anticoagulants.(INR at the same time - increases), therefore, exercising control over anticoagulant therapy, this fact should be borne in mind in the first place and, given it, the patient's blood test should be carried out in one way and in one KDL. Otherwise, you can get inadequate results that adversely affect the further course of anticoagulant therapy, if it is carried out at the time of the study.

The values ​​of prothrombin according to Quick and PTI (prothrombin index) often give the same results in the zone normal indicators. As for the zone of low values, here the results differ markedly, for example, you can get the following test answers: PTI - about 60%, and prothrombin according to Quick - 30%)

Prothrombin index

The prothrombin index (PTI) is the ratio between the clotting time of "healthy" plasma (control) and the clotting time of the blood of a sick person. The result is calculated as a percentage (PTT of normal plasma: PTT of the patient's plasma x 100%), the norm is from 90 to 105%. The inverse ratio (blood clotting time of the patient: the clotting time of "healthy" plasma), expressed as a percentage, is called the prothrombin ratio (PO).

A low prothrombin index and prolongation of the PTT give rise to many pathological conditions:

• Congenital deficiency of some blood coagulation factors (II, V, VII, X);
• Damage to hepatocytes during chronic pathological process, localized in the hepatic parenchyma;
• Syndrome of disseminated intravascular coagulation;
• Hemorrhagic syndrome due to low plasma fibrinogen content (fibrinogenopenia);
• Violation of fibrinogen polymerization (dysfibrinogenemia);
• Vitamin K deficiency;
• Carrying out anticoagulant therapy;
• The use of clotting factor inhibitors, such as heparin, which inhibits the conversion of prothrombin to thrombin.

A high prothrombin index (shortening of the PTT) is noted in the following cases:

1. Formation of blood clots in blood vessels that block the blood flow as a result of various pathological conditions of the hemostasis system (thrombosis);
2. Consumption coagulopathy (DIC);
3. Excessive activation of the anticoagulant system, excessive formation of plasmin (hyperfibrinolysis), which leads first to bleeding, and then (with depletion of plasminogen) to thrombosis;
4. Liver diseases;
5. Increases in factor VII activity ( traumatic injury tissues, necrosis)
6. Inclusion defense mechanisms in women during childbirth.

Thus, prolongation of the PTT will decrease the prothrombin index and indicate a possible hypocoagulation (low clotting blood, tendency to bleed). And, conversely, a reduction in clotting time (PTT) increases the values ​​of the prothrombin index and indicates the presence of signs, that is, increased blood clotting (the risk of developing thromboembolic conditions).

Unity and struggle of opposites

Violation in the hemostasis system leads to the development of coagulopathy, where the pathology that exhibits a tendency to thrombosis is usually denoted by the term, and diseases that are accompanied by increased bleeding are called "hemorrhagic diathesis". Violation of the coagulation abilities of the blood may be hereditary or result from conditions formed in the course of life (hepatic parenchyma diseases, K-avitaminosis, the use of anticoagulants for therapeutic purposes, activation of the fibrinolytic system).

The development of the syndrome of impaired hemocoagulation is due to the loss (or decrease) in the ability of liver cells to biosynthesis of coagulation factors. Moreover, it should be noted that the factors of the systems of coagulation, anticoagulation and fibrinolysis do not exist in isolation, a violation of the activity of any one link leads to pathological conditions other components. For example:

• A disorder in the biosynthesis of the protein we are considering - prothrombin, will certainly lead to a violation of the production of other factors (VII, IX, X) and a deficiency of all components of the prothrombin complex, which will subsequently result in a decrease in FV activity, an increase in the concentration of fibrin monomers, a decrease in FXIII activity and an increase in the ability of fibrin to lysis.
• Violation of fibrinogen metabolism will cause a change in the structural structure of the profibrin layer of blood vessels, opening the way for the movement of erythrocytes through the vascular walls.

The combination of seemingly completely opposite properties of the above systems (under the condition of their normal functioning) ensures the liquid state of blood, freely moving through all the blood vessels of the body, and its coagulation, if there is a need to patch up the gap formed as a result of tissue damage.

Research can be expanded...

If the described methods are not fully informative, studies of the hemostasis system can be expanded, for example, by studying individual functions and quantitative values ​​of platelet and plasma factors. prothrombin test provides a basis for the search for various disorders of hemocoagulation, prompting the direction of further research. For this purpose, they resort to determining other parameters of the hemostasiogram:

1. Indicator of the transition of fibrinogen to fibrin (thrombin time);

At certain diseases prescribe a PTI blood test, what it is and how to decipher it correctly. Blood is considered the fluid tissue of the body. It consists of 4 important components: erythrocytes, platelets, leukocytes and plasma. Platelets are responsible for clotting. The amount of blood in each person is individual, but on average the total volume is from 4.5-5 liters.

The function of the blood is to transport nutrients and oxygen to all organs and tissues, protection against infections and thermoregulation. All this is possible due to its liquid state. However, blood tends to form clots or blood clots, which is also very important for the human body. In case of injury or cuts blood cells react instantly. Due to the ability to clot, the blood forms a clot, which prevents bleeding.

Clots are formed due to a special protein - prothrombin, the precursor of thrombin. Prothrombin is produced by the liver with the help of vitamin K. A blood test for PTI (prothrombin index) allows you to determine the level of clotting. The study of blood functions for coagulability is called a coagulogram.

Description of blood parameters

When assigned, the base parameters are specified. It:



• fibrinogen;
• prothrombin index (PTI);
• PTT, prothrombin time;
• INR, international normalized ratio;
• APTT, activated partial thromboplastin time;
• thrombin time.

PTV, PTI, INR are indicators that determine outer path blood clotting. APTT allows you to determine the internal clotting pathway. The prothrombin index refers to the plasma clotting time. PTI indicators are written as a percentage. Since there are several methods for studying PTI, the indicators differ

In this blood test, reagents with different sensitivities are used. Therefore, WHO decided to use INR instead of IPT. Its norm is not affected by the methods of research and the choice of reagents. To calculate the prothrombin index, the patient's plasma clotting time is noted. At the same time, the clotting time of a standard plasma of a healthy person is recorded. The resulting indicators are called PTI.

The second method of studying PTI is carried out according to Quick. It is considered more reliable and the most popular. The activity of the prothrombin protein is determined using a calibration curve, in which the recording of results depends on normal plasma diluted in specific solutions.

Normal data

Deciphering a blood test for coagulation will help you understand which indicators are within the normal range and which indicate violations associated with serious diseases. The laboratory conclusion indicates the main indicators: fibrinogen, PTI; thrombin time, prothrombin time, APTT, prothrombin.

The amount of fibrinogen normally ranges from 2 g / l - 4 g / l. The increase occurs during pregnancy, infections, heart attack, hypothyroidism, burns, and the use of contraceptives. A decrease in this enzyme occurs with toxicosis, hepatitis, DIC, cirrhosis, treatment with certain drugs, vitamin C or B12 deficiency.

APTT is an indicator that reacts sharply to changes in other coagulation factors. The normal APTT is considered to be 30-40 seconds. This is the time it takes for a blood clot to form. With hemophilia, liver diseases, this figure increases. Thrombin is formed from prothrombin with the participation of vitamin K. Changes occur when the gastrointestinal tract is disturbed.

PTI is considered one of the most important indicators in a blood clotting test. The PTI norm ranges from 93% to 107%. Deviation from the norm is observed in diseases of the liver, pregnancy, taking birth control pills. A decrease in the prothrombin index indicates that blood clotting is impaired. This phenomenon can be observed with a lack of vitamin K, intestinal diseases taking blood-thinning medications (aspirin, cardiomagnyl or diuretics). Poor blood clotting increases the risk of bleeding.

The norm of thrombin time is 11-18 seconds. Thrombin time is the time when the protein fibrinogen is converted to fibrin. Prothrombin time is an indicator of the formation of thrombin from prothrombin (an inactive protein form). The rate of prothrombin according to Quick is 78-142%. Prothrombin time is normally 11-16 seconds.

When is it necessary to test blood for clotting?

The study of blood functions is especially important for pregnant women. This will help eliminate any risk of bleeding during the period of gestation and the upcoming birth. It is necessary to regularly examine blood for coagulability when:

• functional changes in the liver;
• taking medications that affect the process of hematopoiesis;
• pathologies of the circulatory system;
• vascular atherosclerosis;
• autoimmune disorders;
• lack of vitamins;
• antiphospholipid syndrome;
• oncological diseases;
• previous stroke, heart attack;
• preparation for surgery;
• cardiovascular diseases (arrhythmias, angina pectoris, ischemic heart disease).

The reliability of a blood test for a coagulogram depends largely on preparation. Blood sampling is performed from a vein in the morning on an empty stomach or do not eat before blood sampling for about 4-6 hours. If at the time of the analysis the patient takes any medication without fail, it is required to inform the doctor about this. Do not use the day before alcoholic drinks, coffee, strong tea. It is recommended to drink plain non-carbonated water.

The accuracy of the analysis is also affected psychological condition sick. Important to avoid stressful situations, excessive worries and worries. Muscle tension and stiffness adversely affects internal processes organism and can distort the results.

Sometimes the prothrombin index may be higher or lower than normal. this may indicate the presence of serious diseases.

Small changes can be caused not by pathologies, but by a temporary state of a person.

Women who constantly sit on various diets can bring the body to exhaustion. Deficiency of vitamins C, B 12, K affects blood functions.

In this case, an additional examination is prescribed to exclude the presence of pathologies. If the problem is a lack of vitamins, then no special treatment is required. It is enough to adjust the daily diet.

PTI below normal indicates:

• lack of vitamin K;
• an excess of heparin in the body;
• malignant neoplasms in the pancreas;
• amyloidosis (violation of protein metabolism);
• DIC - syndrome;
• renal pathologies;
• gallbladder cancer;
• leukemia;
• pancreatitis in a chronic form;
• dysbacteriosis;
• insufficient production of fibrinogen due to congenital pathologies.

In addition to these factors, the use of antibiotics, antidepressants, corticosteroids, and others affects blood coagulation. medicines. An increase in PTI levels is called hypercoagulability. This means that the blood is too thick, which threatens with blood clots. Hypercoagulability can occur when:

• the formation of malignant tumors;
• polycythemia ( in large numbers erythrocytes);
• thrombosis;
• taking certain medications;
• pregnancy in the third semester.

A high degree of clotting occurs when taking barbiturates, oral contraceptives. In some cases, malnutrition and insufficient fluid intake can lead to thickening of the blood.

Symptoms of bleeding disorders

It is usually impossible to notice problems with blood clotting. But some of the symptoms are suggestive. People with low PTI may have subcutaneous hematomas, when cut, blood oozes longer than usual. Women suffer from heavy menstruation. With poor clotting, nosebleeds occur. See a doctor if you have these symptoms.