Prothrombin time increased reasons. Prothrombin time

What it is? Prothrombin is a protein involved in the blood clotting mechanism; its synthesis occurs in the liver with the participation of vitamin K. Clotting involves the transition of blood from a liquid to a thick state.

To function comfortably in the body, blood must have a liquid consistency. When blood vessels are damaged, a process of coagulation—thickening—must 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, a prothrombin test is taken on an empty stomach. Patient who cannot perform this condition for health reasons, eats 4-5 hours before the procedure.

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

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

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

• Antiphospholipid syndrome in pregnant women (it is manifested by miscarriages, frozen pregnancies, placental insufficiency and other obstetric complications);
• Liver pathologies;
• Atherosclerosis, varicose veins;
• Imbalance of vitamin K in the body;
• Presence of autoimmune diseases;
• Long-term use of anticoagulants indirect action.

The prothrommin test may also be prescribed for other diseases to screen for coagulation. Under a microscope, the natural mechanism of blood clotting is recreated.

Potassium ions and thromboplastin are added to recalcified plasma. The prothrombin complex has several coagulation factors - the analysis allows us to identify 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 normal prothrombin time is from 11 to 16 seconds, but the activity of the substance may vary depending on the sample. Accordingly, draw conclusions by comparing general meaning The result in seconds is incorrect. A relative assessment is required.

Prothrombin index - what is it? (norm)

The prothrombin index is the ratio of the fixed normal blood clotting time to the patient’s individual indicator. Allows you to more accurately determine prothrombin index analysis using INR (international normalized ratio).

The prothrombin index mathematically corrects the prothrombin time. The individual result in seconds is divided by a fixed rate healthy person and multiplied by the sensitivity coefficient 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 rate 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 the patient, suffered a heart attack myocardium or suffering from serious cardiovascular diseases.

The normal prothrombin index is 2.0 – 3.0 in the case of:

• Heart valve defects;
• Chronic atrial fibrillation and taking Warfarin against it;
• Treatment of venous thrombosis and prevention of deep vessel thrombosis after surgery;
• Implantation of mitral and aortic valve prosthesis;
• Treatment of thromboembolism in the pulmonary artery area.

A prothrombin index according to 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 the person has already had ulcerative lesions gastrointestinal tract, renal failure, hypertension and blood flow disorders in the brain. In this case, the potential risk of hemorrhagic (bleeding-related) infarctions in organs increases.

If unsatisfactory results of the analysis using the INR system are obtained, a repeat study is not required (the result is very sensitive and reliable). The index values ​​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 clotting factors.

Prothrombin according to Quick - what is it? (decreased, increased and normal)

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

The construction of the dependence allows you to very accurately estimate the coagulation index, but the sensitivity coefficient of thromboplastin is not taken into account.

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

• The test results card in any laboratory will contain prothrombin according to Quick. The norm is in the range of 78% - 142%. The indicator may be slightly higher than the average, but it should be within normal percentages.

IN healthy body Blood clotting is often increased - hypercoagulation is observed. This process is considered normal until a person develops any vascular diseases or chronic tissue damage. Their presence becomes a risk of blood clots.

Regular screening is necessary after blood thinning medications are prescribed. In some cases, a depot (the stage of accumulation of a substance) can form in the body from these drugs, which will lead to a state of hypocoagulation with increased bleeding.

In addition, the analysis results may also show the opposite process - hypercoagulation (increased coagulation activity). Indicators of insufficient blood density are observed much less frequently than excess blood density.

• However, any pathology of prothrombin factors requires control or even treatment.

Increased prothrombin in men and women

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

• 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 functioning, which also interfere with the normal synthesis of prothrombin;
• Congenital anomalies: deficiency of blood coagulation factors II, V, VII, X;
• The presence of a heparin inhibitor in the coagulation mechanism;
• Nephrotic syndrome, amyloidosis (deposition of a special pathological protein in organs);
• Taking antiseptic, laxatives, anabolic drugs, hormonal drugs, nicotine and acetylsalicylic acid, quinine, quinidine.

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

• Thromboembolism (blockage of blood vessels with blood clots);
• Polycythemia (increased number of red blood cells in the blood, including in connection with oncological processes);
• Oncological diseases: leukemia, cancerous tumors various localizations;
• Pre-infarction state of the body;
• Myocardial infarction.

Prothrombin in women may be increased 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 diseases, birth control pills should be discontinued. Possible transition to hormonal drugs local effects (suppositories, vaginal ring).

Diet does not significantly affect blood clotting. You can reduce the Kwik score by several percent by adding “oxidizing” foods to your daily menu. Increased result causes lack of diet fermented milk products, red and black berries, citrus fruits, fatty fish and the volume of water drunk.

Low prothrombin - what does it mean?

Low prothrombin observed during hypocoagulation. This result indicates the body’s tendency to internal bleeding. A deficiency of coagulation factors occurs in the following situations:

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

A low prothrombin level indicates the following diseases:

• Dysbacteriosis;
• Pathologies of the gastrointestinal tract;
• Prothrombin deficiency;
• Hypovitaminosis.

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

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

Prothrombin during pregnancy

For pregnant women, a test for prothrombin index is done in mandatory. During childbirth, a low reading can lead to heavy bleeding, and a high reading can lead to premature contractions and even late miscarriage.

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

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

Disturbances in the blood clotting mechanism of pregnant women are indicated by:

• Varicose veins on the limbs;
• Bleeding and appearance noticeable bruises after minor damage;
• Improper liver function;
• A long period of lack of results when trying to conceive;
• Conception through the IVF procedure;
• Multiple pregnancy;
• Fetal development lags behind norms;
• Drinking alcohol, smoking by 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. Then the indicator decreases:

1. From the 14th to the 20th week, the prothrombin index according to 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 produces errors at critical values.

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

Prothrombin: normal

IN 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 their area is more than half a hectare. It is impossible to imagine how all this fits 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 disrupt the integrity of the circulatory system, its contents can quickly spill out, threatening a person with death.

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 this that is capable of triggering 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 called blood clotting factors. They are designated by Roman numerals from I to XIII. Prothrombin is one of the main components. This protein is blood clotting factor II.

The name “prothrombin” suggests that it is a precursor to thrombin, an 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 performed as often as clinical blood testing. This procedure is not easy and is prescribed only in cases of extreme necessity, for example in case of blood diseases or problems with blood clotting.

Determination of prothrombin level – the most important test as part of a hemostasiogram.

Norm of prothrombin

Prothrombin molecules disintegrate very easily and quickly. It is difficult to separate them from other proteins, which makes determining its level much more difficult. Several methods are used for qualitative analysis.

• Prothrombin according to Quick. Today this method is generally accepted and widespread. This technique involves calculating the level of a substance as a percentage of permissible quantity. The following values ​​(%) are considered optimal:
  • minimum – 70;
  • maximum – 120.

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

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

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

  The results of the two tests above may be the same if prothrombin is normal. But when its value is lower than optimal, they diverge significantly. The index is highly dependent on the sensitivity of the chemical reagents used in testing.

• Prothrombin time– shows how many seconds it takes the plasma to coagulate after adding a special mixture to it.

  The final test data depends on age. In newborn babies, blood clotting time can range from 14 to 18 seconds. And these indicators are normal. In adults, a period of 10 to 15 seconds is considered optimal.

• International normalized ratio - INR. This method is additional and is used to monitor the results of the prothrombin test.

  The results of such a test allow the doctor to monitor the effectiveness of treatment with anticoagulants - synthetic substances that reduce the level 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 the venous vessels.

  The normal INR is 0.85–1.15.

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

Indications for prothrombin test

A blood test for prothrombin may be prescribed by a doctor in the following 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 in general decreases;
• to monitor coagulation during long-term 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 prescribed to representatives of the fair sex between the ages of 50 and 60. It is at this time that hormonal changes occur, causing change in the composition and structure of blood.

The following doctors can prescribe an analysis:

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

Blood from a vein is used for the study. To ensure that the results are as correct as possible, you must follow the standard rules before the study:

• dinner no later than eight o'clock in the evening, at least 12 hours before testing;
• Before the study, be sure to get your nerves in order and not overexert yourself physically;
• Do not smoke on the day of the test and do not drink strong drinks.

As usual, blood is donated in the morning on an empty stomach. It is necessary to inform medical personnel about all medicines, which were taken in the last 24 hours.

Prothrombin is increased

An increased level of prothrombin in the blood indicates that blood clotting is greater 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 prothrombin levels, and therefore blood clotting:

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

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

• an excess of vitamin K in the body, with the help of which prothrombin is produced;
• use of anticoagulants, antibiotics in therapy, nicotinic acid, hormonal contraceptives. Excessive use of aspirin, anabolic steroids, and laxatives can also affect the increase in prothrombin.

Quite often, the protein content increases during pregnancy. Most often it appears in the last trimester and does not require treatment.

Prothrombin is reduced: reasons

A reduced level of prothrombin is dangerous because even a minor injury that damages a blood vessel can result in significant blood loss. After all, the formation of a blood clot occurs more slowly than it should.

A decrease in prothrombin levels is provoked by the following reasons:

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

It is possible to bring the prothrombin level back to normal, but anything 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/prothrombin.html

Prothrombin (according to Quick) and prothrombin index, normal

The prothrombin test is part of the blood clotting test - coagulogram.

In addition to the activity of this protein, indicators such as PI (prothrombin index, or PTI) and PT (prothrombin time) are also determined, allowing one to evaluate the rate of coagulation.

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 clotting. Its production occurs in the liver in the presence of many substances. In particular, vitamin K, deficiency of which leads to the synthesis of incorrect prothrombin molecules - they form blood clots that disrupt blood flow and can be fatal.

A prothrombin test is needed to assess blood clotting, and the most accurate and universal test method is PC - prothrombin according to Quick. 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 patient's plasma clotting time to the time of this process in the sample.

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

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

List of indications to carry out the prothrombin analysis according to Quick:

• impaired blood clotting;
• liver diseases;
• 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.).

Help: Vitamin K is produced by bacteria in the intestines and is actively involved in the formation of prothrombin. Both its deficiency and its excess negatively affect the rate of blood clotting.

A PC test is necessary to monitor the hemocoagulation system during the 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 diseases. Therefore, at this age it is especially important to regularly get tested for prothrombin.

Prothrombin time - what is it?

Depending on the causes of bleeding, blood can begin to clot along two routes - internal or external. The first is activated if the vessels are damaged externally - as a result of a bruise, cut, scratch, bite, or abrasion. The internal pathway works when the integrity of the blood vessel wall has been damaged from the inside - 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 “repairing” vessels that have been damaged by compounds circulating through the bloodstream. In test results, prothrombin time may be referred to as PT, ecombipl RT or RT.

Prothrombin time is increased, compared to the norm, in the following conditions:

• lack of vitamin K;
• initial stage of DIC syndrome;
• liver pathologies;
• taking drugs from the group of anticoagulants - Thromboassa, Aggregal, Warfarin, Heparin and others;
• hemorrhagic diathesis of newborns;
• inflammation and blockage of the biliary tract;
• Zollinger-Ellison syndrome;
• impaired absorption of fats in the intestines;
• deficiency of coagulation factors - fibrinogen, prothrombin, AC globulin, proconvertin and Stewart-Prower factor.

The lower the concentration of prothrombin in the blood, the higher the prothrombin time, because the blood clotting process occurs more slowly.

Prothrombin time is decreased, if the following conditions occur:

• pregnancy;
• DIC syndrome;
• 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.

Low prothrombin time during the test may be due to long-term storage of plasma before the test and irregularities during blood collection.

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 prothrombin index test depends on the sensitivity of the drugs used in the laboratory. Therefore, it cannot be called universal, unlike the Quick prothrombin test.

Increased 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 impair the functioning of fibrin;
• hereditary and acquired pathologies leading to a deficiency of coagulation factors (amyloidosis, liver disease, nephrotic syndrome).

Increased prothrombin also appears with long-term use drugs:

• antibiotics;
• diuretics;
• Aspirin;
• indirect anticoagulants;
• anabolic steroids;
• Methotrexate;
• laxatives;
• nicotinic acid;
• Heparin and other clotting inhibitors.

Prothrombin norm, table

The extreme values ​​of PC are figures below 78 and above 142%. Prothrombin standards according to Quick are presented in the table.

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

Low prothrombin

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

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

The decrease in PC can be explained by this dependence - the activity of the prothrombin protein is high, the blood clots faster compared to the control plasma sample, therefore the Quick test for prothrombin is lower than 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 a mandatory part of the tests for pregnant women. Evaluation of this study, including prothrombin tests, allows for the timely identification of conditions dangerous to the health of the child and the expectant mother.

Prothrombin according to Quick during pregnancy is normally slightly reduced, that is, the activity of the coagulation system increases. This is due to the emergence of a new blood circulation and the body’s preparation 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 labor.

Severe bleeding due to 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 reasons postpartum mortality.

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

• The normal prothrombin index for women carrying a child is 80-100%. When its values ​​are high, in order to avoid thrombosis and other complications, drugs that reduce increased coagulation activity are indicated.
• Low PI, on the contrary, carries a 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 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 obtain 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 complex study, so it is prescribed in special cases: for screening tests, blood diseases, problems with clotting.

What is the normal level 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 it takes the patient’s blood to clot.
3. The prothrombin index, or abbreviated as PTI, is the ratio of normal prothrombin time to the parameters of the patient being examined.
4. INR - international normalized ratio - is the opposite of PTI. It shows the ratio of the patient's prothrombin time to the normal prothrombin value.

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

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

For both men and women, the prothrombin rate remains the same. Any deviations from the norm are a cause for concern. Can contribute to an increase or decrease in prothrombin levels various diseases, some of which represent 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. The following factors can provoke this:

1. The production of prothrombin is associated with vitamin K. Increased quantity This protein in the blood indicates an excess 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 jump during pregnancy. Especially in the later stages.
5. Prothrombin may also increase in patients suffering from liver problems.
6. Sometimes excess protein occurs due to the use of Aspirin, hormonal contraceptives, diuretics, corticosteroids, anabolic steroids, and laxatives.
7. Thromboembolism and polycythemia cause an increase in prothrombin.

Why is prothrombin below normal?

A decrease in prothrombin does not have a very good effect on health either. It is caused by the following 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. A prothrombin test will show a value below normal if the patient is taking drugs that increase clotting.
3. The level of prothrombin decreases with vitamin K deficiency. Most often, the problem develops against the background of dysbiosis and diseases of the gastrointestinal tract.
4. A lack of fibrinogen negatively affects test results. Moreover, deficiency can be congenital or acquired.

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

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Laboratory measurement

Normal value

The normal prothrombin time is 11-16 seconds, for INR it is 0.8-1.2. When treated with oral anticoagulants (warfarin), a higher target INR level is required - usually in the range of 2-3.

Methodology

When determining prothrombin time, blood plasma is most often used. The 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. The analysis is then 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 laboratories will refuse to perform a test if the tube is not completely filled with blood - and thus contains a relatively large volume of citrate. Next, tissue factor (also known as clotting factor III) is added to the calcium-containing plasma and the time until clot formation is measured, which is determined by optical measurement. Some laboratories use mechanical detection of the moment of clot formation, which allows more accurate determination of PTT in the case of a large number of fat droplets in the plasma and in cases of hyperbilirubinemia.

Prothrombin index

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

International normalized ratio

Prothrombin time results in healthy individuals vary depending on the type of tissue factor reagent (thromboplastin) used in different laboratories. The INR value was introduced into clinical practice to standardize the results of the PTT test. Manufacturers of the reagent (tissue factor) for the PTT test are required to indicate the ISI (international sensitivity index) for the reagents. The MIF indicates the tissue factor activity in a given manufactured batch of reagent in comparison with 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= (Patient's PTT/PTT normal) MICH

Interpretation

Prothrombin time is the time it takes for a clot to form after tissue factor is added to the plasma (the reagent is obtained from animal tissue). This indicator allows you to evaluate the external and general pathways of blood coagulation. The rate of blood coagulation along the extrinsic pathway strongly depends on the concentration of coagulation factor VII. Factor VII is a protein with a short lifespan; vitamin K is required for its synthesis. PTT can be prolonged as a result of vitamin K deficiency that occurs when using warfarin (a desirable clinical effect), with maladsorption syndrome, with insufficient bacterial colonization of the intestine (for example, in newborns) . In addition, insufficient concentration of factor VII can be observed in liver diseases (impaired synthesis), or increased consumption of factor (DIC syndrome), which also prolongs PTT. When INR is above 5.0 - observed high risk bleeding, with an INR below 0.5 - a high risk of thrombosis. Normal INR values ​​in healthy individuals range from 0.8 to 1.3. For 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 during the perioperative period.

State	PTV	APTT	Bleeding time	Platelets
vitamin K deficiency or warfarin therapy	Lengthened	Lengthened	Without changes	Without changes
DIC syndrome	Lengthened	Lengthened, 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 afibyrinogenemia	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, influences PTT results depending on the technique used. Variations in reagent (tissue factor) activity result in decreased INR accuracy, despite attempts international standardization PTT (INR administration) in 2005 still had significant differences in the rates determined in different laboratories.

Statistics

Every year, about 800 million INR/PTT tests are performed worldwide.

Express determination

Except laboratory method determination of INR described above, a rapid method that allows you to monitor INR at home is becoming increasingly popular. A new generation of devices and reagents for rapid tests allows you to obtain results that are close in accuracy to laboratory results. 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 into thrombin, representing the duration (in seconds) of the formation of a clot in the blood plasma under study in the presence of thromboplastin and ... ... Big medical dictionary

The time required for blood to clot after calcium and thromboplastin are added to the blood sample being tested. A long prothrombin time (compared to the control sample) indicates the presence of a deficiency of coagulating substances in the body... ... Medical terms

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

- (A. J. Quick, born in 1894, American doctor) see Prothrombin time ... Large medical dictionary

- (Greek haimorrhagia bleeding) a group of diseases and pathological conditions of a hereditary or acquired nature, the common manifestation of which is 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: Antifungal agents Nosological classification (ICD 10) ›› B20.4 Disease caused by HIV, with manifestations ... ... Dictionary of medicines

I Anticoagulants (anticoagulantia; Greek anti against + Latin coagulans, coagulantis causing clotting) drugs that reduce blood clotting by inhibiting the formation of fibrin. A distinction is made between direct and indirect action.… … Medical encyclopedia

Article instructions. The text of this article almost completely repeats the instructions for use of the drug provided by its manufacturer. This violates the rule against instructions in encyclopedia articles. Also... Wikipedia

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

Quite often, special laboratory tests reveal that the patient has elevated levels. What could such a change indicate? How dangerous is this condition? Why is it necessary to determine prothrombin time, and who are these tests indicated for? These questions interest many.

What is prothrombin time?

It's no secret that blood clotting processes 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 prothrombin time is, you need to consider general mechanism coagulation. Damage to the vascular wall causes activation special complex enzymes that ensure the formation of fibrin threads. In turn, these threads become a strong framework for the 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 determine how quickly the blood coagulation system works when activated externally.

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 normal PT should be from 11 to 16 seconds, and in order to obtain accurate data on the functioning of the body, additional tests are necessary.

IN modern medicine The 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 something like in the following way: PT of the patient/PT of normalized plasma (the result is raised to the power of the so-called international thromboplastin sensitivity index).

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

Today it is the most accurate test. This test compares the patient's prothrombin complex activity with that of control plasma.

Indications for research

In fact, there are many diseases and disorders that affect the process. That is why such research 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.

This same test is used in conjunction with some other procedures to evaluate liver function. If a deficiency or metabolic disorder of vitamin K is suspected, patients are also sent for analysis. Prothrombin and in pregnant women, since this period of life is associated with some risks.

How are samples collected?

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

In fact, no special preparation is required for testing. Blood is donated on an empty stomach, so in most laboratories blood is drawn in morning time(until 11 o'clock). Most likely, you will receive test results the very next day. It's also worth noting that some factors can skew the results, so be sure to consult your doctor before testing.

How is prothrombin time determined in the laboratory?

Determining prothrombin time is a relatively simple procedure. As mentioned, after collection, 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 this, the required amount of calcium is added to the sample, and then tissue blood. Then the time it takes for a blood clot to form is measured. As already mentioned, it should be 11-16 seconds.

Increasing performance

Is it dangerous if prothrombin time is elevated? Unfortunately, test results do not always correspond normal value. What disorders are associated with 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 liver diseases and liver failure.
• The cause may also be DIC syndrome.
• With developing hypovitaminosis K, the prothrombin time is also increased. In turn, a deficiency of this vitamin can occur with dysbiosis, malabsorption syndrome, as well as some diseases of the gallbladder and pancreas.
• The use of some anticoagulants leads to an increase in PT.
• Massive blood transfusion may also affect the results of the study.

If the indicator is reduced

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

Quite often, a decrease in PT indicates the presence or risk of thrombosis, which is extremely dangerous, as it is often a threat to the patient’s life. A decrease in the indicator is often associated with taking certain groups of hormonal contraceptives. Polycythemia may also be a cause. Pregnant women's 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 medications may increase the duration of thrombus formation. But there are some other restrictions.

In particular, the results of the study will be false if you are taking aspirin, barbiturates, or medications 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, such disorders disrupt the absorption of vitamins and minerals, including tocopherol (vitamin K).

If you eat foods that contain large amounts of vitamin K, the test results may be inaccurate. A few days before the test, limit the amount of pork and beef liver, soy products, peas, green tea, cabbage, greens and broccoli.

Alcohol abuse also affects the blood clotting process, so, again, you should avoid alcoholic beverages a few days before testing.

Factors affecting PT include taking laxatives and some homeopathic medicines.

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

Why determine prothrombin time for a pregnant woman?

It's no secret that during pregnancy a woman's body (especially the circulatory and endocrine system) is undergoing significant changes. That is why determining prothrombin time during pregnancy is extremely important.

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 become too thin. In such cases there is big risk massive blood loss, especially during childbirth. Determining prothrombin time allows the doctor to timely identify this or that disorder and prevent the development of complications.

Prothrombin, prothrombin index and time: blood standards, interpretation of tests

As a rule, when applying for hospital treatment, each patient takes a test the next morning before breakfast mandatory tests from the finger (complete blood count, sugar and prothrombin). These laboratory tests are considered to be the main indicative studies, since they are the ones who “draw” big picture the patient's condition. Other (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, in the process of 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 through blood vessels, according to its characteristics, is classified as connective tissue. Being in a liquid state and possessing fluidity, which prevents the gluing of formed elements, blood, at the same time, is able to quickly clot when the vascular wall is damaged. She has this 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 without any 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's important to note that prothrombin production will become noticeably more difficult if the amount of vitamin K in the body decreases for some reason, which 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 the need arises.

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

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

Importance of the prothrombin complex

The deficiency of this factor can be either congenital or developed during life. Congenital prothrombin deficiency is not so common, that is, it is a rare pathology. Low prothrombin from birth is caused by 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 diseased liver (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 called K-dependent) give a sharp drop in the concentration of this indicator.

Reduced prothrombin levels cause blood to take longer 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 one to have an idea of ​​​​the state of the entire prothrombin complex:

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

Excessive activity of prothrombin without any need is also fraught with various troubles, and sometimes even disaster for the body. Increased coagulability, the formation of clots that can close a vital blood vessel, can result in dangerous situation, even death.

Rough tests and full analysis

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

As for the prothrombin test, it is a very important component and can be presented in various forms. The deficiency of prothrombin complex factors (II, V, VII, X) is determined mainly by analyzing 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 using the principle of replacement samples.

Meanwhile, we cannot ignore the indicators of blood coagulation capacity in women during planning or pregnancy, because this allows us to calculate possible risks during childbirth. Keeping in mind these indicators during pregnancy, it is possible to anticipate and prevent bleeding (if PTT is prolonged) or the development of thrombosis and premature placental abruption if the blood exhibits a particularly high tendency to clot. During the period of labor itself, 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 blood coagulation function only with prothrombin complex indicators is not enough. In order to have a complete picture of the functional capacity of the hemostatic system, expectant mothers are prescribed the maximum coagulogram indicators.

Prothrombin time

Prothrombin time as laboratory test, allows clinicians to quickly assess not only the external hemostatic system, but also the entire cascade of blood coagulation reactions.

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

Tissue (cellular) thromboplastin, called tissue factor (TF), interacting with coagulation factors (FVII) circulating in the bloodstream, sequentially includes other plasma thromboplastic factors in the process. This means that the hemocoagulation system is activated and the first phase of coagulation begins - the conversion 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 blood 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 infants – 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 prolonged) in the following pathological conditions:

1. Liver diseases, because prothrombin synthesis occurs there;
2. Lack of vitamin K, the participation of which is necessary for the synthesis of K-dependent factors (including prothrombin);
3. Increasing level blocking thrombin and other factors of the hemocoagulation system;
4. Increasing the fibrinolytic ability of blood (dissolving clots);
5. Pancreatic cancer;
6. Certain hematological pathologies (myeloid metaplasia);
7. GrBN ( hemorrhagic disease newborns);
8. High level of red blood cells in the blood (above 6.0 x 10 12 / l);

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

PTT, Quick's test or thromboplastin time is an indicator of the external system of activation of factor II, where prothrombin time depends on the concentration of fibrinogen in the blood plasma, factors V, VII, X. The rate of PTT (Quick's 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 prothrombin complex factors as a percentage of the norm. This method is currently considered one of the most in meaningful ways prothrombin studies.

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

Normal prothrombin values ​​according to Quick vary within a wider range than PTI, and normally range from 75 to 140%. Among women upper limits standards are usually lower. The results of the analysis may depend on the age of the patient, the treatment he is taking (anticoagulants), and 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, when exercising control over anticoagulant therapy, this fact should be kept in mind first of all and, taking it into account, the patient’s blood should be analyzed in one way and in one CDL. Otherwise, you may obtain inadequate results that negatively affect the further course of anticoagulant therapy, if it is carried out at the time of the study.

Prothrombin values ​​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 vary noticeably, 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 patient plasma x 100%), the norm is from 90 to 105%. The inverse ratio (clotting time of the patient’s blood: clotting time of “healthy” plasma), expressed as a percentage, is called the prothrombin ratio (PR).

A low prothrombin index and prolonged PTT result in many pathological conditions:

• Congenital deficiency of certain blood clotting factors (II, V, VII, X);
• Damage to hepatocytes during chronic pathological process, localized in the liver parenchyma;
• Disseminated intravascular coagulation syndrome;
• Hemorrhagic syndrome caused by low plasma fibrinogen content (fibrinogenopenia);
• Impaired 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 (shortened PTT) is observed in the following cases:

1. Formation of blood clots in blood vessels blocking blood flow as a result of various pathological conditions of the hemostasis system (thrombosis);
2. Consumption coagulopathies (DIC syndrome);
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. Increased factor VII activity ( traumatic injury tissue, necrosis);
6. Inclusion defense mechanisms in women during childbirth.

Thus, prolongation of PTT will reduce 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 (risk of developing thromboembolic conditions).

Unity and struggle of opposites

Disturbances in the hemostasis system lead to the development of coagulopathies, where pathology that shows a tendency to thrombosis is usually designated by the term, and diseases that are accompanied by increased bleeding are called “hemorrhagic diathesis.” Violations of blood coagulation abilities can be hereditary in nature or result from conditions formed during life (diseases of the liver parenchyma, vitamin K deficiency, the use of anticoagulants for medicinal purposes, activation of the fibrinolytic system).

The development of hemocoagulation disorder syndrome is caused by the loss (or decrease) of the ability of liver cells to biosynthesize coagulation factors. Moreover, it should be noted that the factors of the coagulation, anticoagulation and fibrinolysis systems do not exist in isolation; disruption 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 entail a disruption in 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 the activity of FV, an increase in the concentration of fibrin monomers, a decrease in the activity of FXIII and an increase in the ability of fibrin to lysis.
• Disruption 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 red blood cells through the vascular walls.

The combination of seemingly completely opposite properties of the above systems (provided they are functioning normally) 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 a 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 searching for various hemocoagulation disorders, suggesting the direction of further research. For this purpose, they resort to determining other parameters of the hemostasiogram:

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

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

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

Clots are formed due to a special protein - prothrombin, a 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 clotting functions is called a coagulogram.

Description of blood parameters

When assigned, the basic parameters are specified. This:



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

PTT, PTI, INR - indicators that determine outer path blood clotting. APTT allows determination of the intrinsic coagulation pathway. The prothrombin index refers to the plasma clotting time. PTI indicators are written as percentages. Since there are several methods for studying PTI, the indicators differ

This blood test uses reagents that have different sensitivities. Therefore, WHO decided to use INR instead of IPT. Its rate is not affected by research methods and the choice of reagents. To calculate the prothrombin index, the patient's plasma clotting time is noted. In this case, the clotting time of standard plasma from 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 most popular. Prothrombin protein activity is determined using a calibration schedule, in which the recording of results depends on normal plasma diluted in specific solutions.

Data on normal indicators

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

The normal amount of fibrinogen ranges from 2 g/l to 4 g/l. An increase occurs during pregnancy, infections, heart attack, hypothyroidism, burns, and use of contraceptives. A decrease in this enzyme occurs with toxicosis, hepatitis, DIC syndrome, cirrhosis, treatment with certain drugs, deficiency of vitamin C or B 12.

APTT is an indicator that reacts sharply to changes in other clotting 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 and liver diseases, this figure increases. Thrombin is formed from prothrombin with the participation of vitamin K. Changes occur when the gastrointestinal tract is disrupted.

PTI is considered one of the most important indicators when testing blood for clotting. The PTI norm ranges from 93% to 107%. Deviation from the norm is observed in liver diseases, pregnancy, taking birth control pills. A decrease in the prothrombin index indicates that blood clotting is impaired. This phenomenon can occur 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 normal thrombin time is 11-18 seconds. Thrombin time is the time when fibrinogen protein is converted into fibrin. Prothrombin time is a measure of the formation of thrombin from prothrombin (an inactive form of protein). The prothrombin rate according to Quick is 78-142%. The normal prothrombin time is 11-16 seconds.

When is it necessary to test blood for clotting?

Blood function tests are especially important for pregnant women. This will help eliminate any risk of bleeding during pregnancy and the upcoming birth. It is necessary to regularly test blood for clotting if:

• 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;
• suffered a stroke, heart attack;
• preparation for surgery;
• cardiovascular diseases (arrhythmias, angina, ischemic heart disease).

The reliability of a blood test for a coagulogram depends largely on preparation. Blood is drawn from a vein in the morning on an empty stomach or without eating for about 4-6 hours before blood sampling. If during the analysis the patient takes any medications without fail, the doctor must be informed about this. It is forbidden to consume the day before alcoholic drinks, coffee, strong tea. It is recommended to drink plain still water.

The accuracy of the analysis is also affected psychological condition sick. It is important to avoid stressful situations, excessive worries and worries. Muscle tension and stiffness negatively affects internal processes body and may distort the results.

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

Small changes may be caused not by pathologies, but by a person’s temporary condition.

Women who are constantly on various diets can bring their body to exhaustion. Deficiency of vitamins C, B12, 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 your daily diet.

PTI below normal indicates:

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

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

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

A high degree of coagulation occurs when taking barbiturates and oral contraceptives. In some cases, poor nutrition 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 symptoms suggest this. People with low PTI may experience subcutaneous hematomas When cuts occur, blood oozes out longer than usual. Women suffer from heavy menstruation. When clotting is poor, nosebleeds occur. If you have these symptoms, visit your doctor.