Elevated levels of alkaline phosphatase in the blood. Alkaline phosphatase - what will the test tell you? Rules for preanalytical preparation for the patient

With the help of alkaline phosphatase (ALP), reactions associated with the removal of phosphate from organic compounds are activated in the body. The enzyme is a hydrolase, which means it converts biochemical substrates by adding water elements. It promotes the smooth movement of phosphorus throughout the body.

The peak activity of alkaline phosphatase is fixed in a pH environment, which is why its name contains “alkaline”.

The enzyme level reflects the condition of the bone tissue and hepatobiliary system (gallbladder and bile ducts, liver). Also, by its content in the blood one can judge the correspondence of phosphorus-calcium metabolism to the needs of the body.

An increased content of the enzyme is observed both in physiological conditions of the body and in severe pathologies.

Symptoms of increased alkaline phosphatase

An increase in the amount of alkaline phosphatase compared to the norm can be manifested by the following symptoms:

feeling tired;
pain in the right hypochondrium;
loss of appetite;
attacks of nausea;
painful sensations in bones and joints.

Such manifestations signal an unhealthy state of the body. They are characteristic of many diseases, so it is simply necessary to conduct a blood composition study. The results of the analysis will provide information about the enzyme content.

Alkaline phosphatase is elevated: causes

An increase in the concentration of alkaline phosphatase is observed in relatively healthy people in the following cases:

alcohol poisoning;
long-term use of medications. Their list is quite extensive and contains several hundred items. Particularly dangerous are drugs that can cause the so-called hepatotoxic effect. This means that their long-term use will easily disrupt the structure and function of the liver;
pregnancy.

An increase in enzyme levels associated with pathologies most often occurs during the development of diseases that damage bone tissue, liver and kidneys.

Three groups of such ailments can be distinguished.

I. Damage to the liver, its destruction (destruction) and problems with the movement of bile:

Cirrhosis is a painful process in which normal organ tissue is replaced by scar tissue. All liver functions are inhibited.
Hepatitis, most often viral and autoimmune. With this disease, the content of alkaline phosphatase exceeds the norm three times.
Primary tumor in the liver and secondary cancer - penetration of metastases of tumors that have arisen in other organs.
Primary sclerosing cholangitis is a chronic liver disease that results in inflammation, development of liver failure and portal hypertension. The disease is rare.
Primary biliary cirrhosis is a consequence of a previous illness. A day or two after the onset of the disease, the level of alkaline phosphatase increases fourfold and does not decrease even after recovery. It will take at least a week before the enzyme levels return to normal levels.
Infectious mononucleosis is an acute viral disease. The liver is affected, and peculiar changes occur in the composition of the blood.
Cholestasis is stagnation of bile.
Extrahepatic obstruction of the bile ducts by stones that interfere with the outflow of bile.

II. Pathological changes in bone tissue:

Paget's disease is a chronic and complex disease. The bone repair mechanism is damaged, which leads to increased destruction, deformation and weakening.
Osteomalacia is a systemic skeletal disease that is accompanied by softening and deformation of bones. The disease disrupts mineral metabolism, and phosphoric acid, calcium salts and vitamins leave the body.
Osteogenic sarcoma is a malignant primary bone tumor. It originates and develops directly in their depths.
Metastases that have penetrated into the bone structure from other organs.
Increased metabolism in bone tissue. It occurs during the healing process of fractures.

III. Other diseases:

Primary hyperparathyroidism is a disease of the endocrine system caused by increased activity of the parathyroid glands. It is accompanied by a pronounced disturbance in the metabolism of phosphorus and calcium.
Heart attack.
Ulcerative colitis.
Intestinal perforation.

Medical statistics inform that in more than half of patients, alkaline phosphatase levels exceeding the norm are caused by liver pathologies.

Features of increasing alkaline phosphatase in men and women

The normative amount of alkaline phosphatase in men is higher than in the fair sex. Over the years it changes in both sexes and tends to increase.

Abnormal amounts of naturally occurring ALP result in:

excessive or intense physical activity;
vitamin deficiency and dietary errors.

In the fair sex, the enzyme level increases:

during the period of gestation, mainly in the third trimester;
during breastfeeding;
after menopause.

Women who take hormonal contraceptives are more likely to develop a disease such as cholestatic jaundice or intrahepatic cholestasis.

And men who are already 50 years old often suffer from Paget's disease. This disease can be inherited.

Features of alkaline phosphatase growth in children

The amount of enzyme and its activity in children is always higher than in adults.

This situation can continue until the onset of puberty. All this is natural and is explained by the peculiarities of the physiology of children, because they experience rapid growth of bone tissue.

At the same time, data on the content of alkaline phosphatase help diagnose liver pathologies, which are accompanied by insufficient supply of bile to the duodenum. The enzyme level in such ailments often increases and becomes much higher than the normal value.

An increased amount of ALP in children signals the possible development of the following diseases:

rickets;
hyperparathyroidism;
Infectious mononucleosis;
intestinal infection;
damage to bone tissue, including malignant tumors;
Paget's disease.

For timely diagnosis of rickets, recording the level of alkaline phosphatase is invaluable. An increase in enzyme content during the development of this disease occurs much earlier than the first symptoms appear.

Alkaline phosphatase is higher than normal: what to do?

First of all, do not self-medicate. Enzyme growth is not a disease, but only a symptom that accompanies a specific illness.

It should also be taken into account that elevated levels of ALP can be natural. Excessive enzyme activity is sometimes observed in healthy people. In these cases, it is a consequence of physiological characteristics and processes in the human body.

Therefore, only a specialist can find out the real reasons for the increase in enzyme levels. He will prescribe additional tests, based on the results of which he will accurately diagnose the disease and decide on therapy.

In order for the alkaline phosphatase level to normalize, it is necessary to cure the underlying disease. Simply adjusting the indicator to the optimal limits will not work.

Causes of elevated alkaline phosphatase

Deviation of alkaline phosphatase from the norm may indicate cancer, cirrhosis, bile stagnation, and pathological processes that develop in bone tissue. This is explained by the fact that this component is an enzyme that allows a specialist to assess the condition of a person’s bone tissue, his liver, gallbladder, and bile ducts. In a pregnant woman’s body, the compound indicators reflect the condition of the placenta. Considering the seriousness of diseases that can cause enzyme deviations from the norm, it is very important to find out in time the reasons why alkaline phosphatase is increased or decreased and begin treatment.

Connection characteristics

Alkaline phosphatase is involved in the transport of phosphorus throughout the body. This enzyme is present on the cell membranes of bones, intestinal mucosa, walls of the placenta, bile ducts of the liver, mammary gland during lactation, as well as in other tissues of the body, where reactions occur that cause the splitting of phosphate from organic compounds.

Alkaline phosphatase is produced by osteoblasts - large young bone tissue cells that produce the intercellular matrix substance and are located in places where bone is actively formed. As the intercellular substance accumulates, osteoblasts become immured in it and transform into osteocytes (as bone tissue cells are called).

The level of alkaline phosphatase in the blood varies greatly with age and gender. In a child’s body, the amount of enzyme is at a very high level and is several times higher than that of an adult. This is due to the fact that alkaline phosphatase takes an active part in the formation of the skeleton.

There is a difference in the concentration of the substance in men and women: in the male body the level of the enzyme is much higher than in the female. With excessive physical exertion, its amount may even exceed the norm. The amount of alkaline phosphatase also changes during pregnancy: its concentration in the body increases.

When searching for data on what values are considered normal, you need to know that figures in different sources may differ significantly, since laboratories use different measurement methods. Therefore, when interpreting data, you need to take into account the standards indicated by the laboratory on the analysis form next to the decoding of personal data.

Decoding the results

The doctor prescribes a biochemical test to determine the level of alkaline phosphatase in the blood if the patient complains of pain in the bones and joints. This condition may be accompanied by constant fatigue, loss of appetite, attacks of nausea, and pain in the right hypochondrium. It is worth noting that such symptoms can be caused by different reasons, so it will be necessary to do different blood tests. Including - determining the concentration of alkaline phosphatase.

If the analysis showed that alkaline phosphatase exceeded the norm, this means that the cell on the membrane of which the enzyme should be present is damaged, and the component has entered the bloodstream. Sometimes this can be caused by physical reasons, for example, overexertion or long-term use of medications or contraceptives. Therefore, the doctor, in order to confirm or refute the decoding of the data, prescribes a repeat analysis.

According to statistics, in most cases, the cause of elevated alkaline phosphatase levels is liver damage. However, this is not the only situation in which deviations from the norm are observed.

The amount of alkaline phosphatase increases in the blood for the following reasons:

Stagnation of bile due to blockage of the bile ducts with stones or compression by a tumor.

Metastases that have entered the liver from a cancerous tumor that has developed in another organ.

Hepatitis, cirrhosis, cancer and other serious liver diseases.

Malignant tumor in the biliary tract.

Various pathologies in bone tissue. For example, Paget's disease, when the bone repair mechanism is damaged, causing them to become deformed and weaker.

Bone cancer, as well as metastases that have penetrated into the bone tissue from other organs.

Diseases caused by disturbances in the metabolism of calcium and phosphorus (rickets, hyperparathyroidism) or their deficiency in the body.

Infectious mononucleosis is an acute viral disease that causes liver damage.

Increased bone metabolism, which is usually observed during fracture healing.

Ulcerative colitis.

Heart attack.

Intestinal perforation.

Alcoholism.

A blood test may show high levels of alkaline phosphatase due to long-term use of medications, especially medications that damage the liver. A woman may have this if she is taking contraceptives, which she takes to prevent pregnancy.

Another reason for deviations from the norm in the results of a blood test is menopause, when the female body begins to develop osteoporosis (the density and structure of bone tissue decreases).

Alkaline phosphatase is usually reduced in hypothyroidism, anemia, and severe dystrophy. Low enzyme levels can also be caused by hypophosphatasemia. This is a rare disease that disrupts the mineralization of bones and teeth. Symptoms of the disease include breathing problems, convulsions, muscle weakness, and bone pain.

During pregnancy and in babies

In the body of a pregnant woman, the concentration of alkaline phosphatase usually increases in the third trimester, even during a normal pregnancy, and is also observed during lactation. However, significant deviations during pregnancy are not the norm, and therefore are considered by doctors as a signal of the development of pathological processes. For example, this is possible with eclampsia, when blood pressure reaches such a high level that it can damage the placenta and also pose a danger to the life of the pregnant woman and the child.

Increased enzyme activity is observed in premature babies who grow very quickly. In a full-term baby, the enzyme is also at a high level, although to a lesser extent. But if its concentration in children exceeds the norm, this means that the child may develop rickets. It is noteworthy that with this disease in children, a deviation of alkaline phosphatase from the norm is observed much earlier than the first symptoms of the disease make themselves felt. This means that thanks to the analysis, doctors can prescribe treatment in a timely manner and prevent the development of the disease in the child.

Features of therapy

If a blood test shows an enzyme deviation from the norm in adults and children, in no case should you self-medicate. Many diseases that cause alkaline phosphatase levels to rise or fall are deadly. In addition, a biochemical blood test alone will not allow a doctor to detect the cause and make an accurate diagnosis. Therefore, it will be necessary to undergo additional examinations.

You need to know: the level of alkaline phosphatase in the blood of adults and children will stabilize no earlier than the underlying disease is cured. If the problem is poor nutrition, it must be corrected: food must be saturated with all the vitamins and minerals that cells need for growth and development. The diet may need to be supplemented with vitamin and mineral complexes.

In the case of hepatitis, cirrhosis, oncology and other diseases, everything is much more complicated and depends on the stage of the disease at which the disease was discovered. If the disease was detected at an early stage, when symptoms have not yet appeared, the prognosis is favorable. A disease discovered at a later date is more difficult to cure.

Alkaline phosphatase (ALP): the norm in children and adults, why it is increased and decreased

A number of enzymes included in the list of biochemical blood tests (BAC) under the general name “alkaline phosphatase” perform certain duties in the body, namely, they cleave off phosphoric acid residues from its organic ester compounds. By performing this work, they take part in calcium-phosphorus metabolism.

Alkaline phosphatase (ALP) is a component of the cell membranes of almost all tissues of the body: bone, glandular, epithelial, but the enzyme exhibits the greatest activity in the cells of the liver, kidneys, bone tissue and intestinal epithelium.

Phosphatase – a series of isoenzymes

Alkaline phosphatase in the human body is represented by a total of 11 isoenzymes, but the most important and often discussed are:

As part of a biochemical blood test, alkaline phosphatase is often prescribed when examining children, because bone growth is accompanied by an increase in its activity (in children it is increased compared to normal levels in adults).

The activity of alkaline phosphatase in blood serum changes when calcium-phosphorus metabolism is disturbed, therefore it serves as a unique marker for the early detection of pathology of the skeletal system in older people (osteoporosis) and is used for screening studies.

Some neoplastic processes localized in the female reproductive organs lead to an increase in the placental fraction (cervical cancer), which in a blood test will be manifested by a digital increase in the activity of total alkaline phosphatase.

Enzyme activity in children and adults

ALP activity in childhood is normally 1.5 times higher than in adults, and since a child grows and develops intensively from birth to a certain time, the numbers characterizing ALP can be very high and reach 800 U/l . However, this does not give cause for concern, since this situation is due to the presence of not only liver, but also bone enzymes in ALP. In people whose skeletal system has completed its formation, the liver isoenzyme plays the main role in increasing the activity of alkaline phosphatase.

The activity of the isoenzyme is noticeably increased in pregnant women (closer to childbirth - the third trimester), after all, the fetus demands its own, and in premature babies, since the child must intensively catch up with his peers. Such indicators are physiologically determined and are taken as normal values corresponding to these conditions. Meanwhile, reduced activity of alkaline phosphatase in pregnant women indicates underdevelopment of the placenta, which is taken into account by the doctor monitoring the woman.

Table: norms of alkaline phosphatase in the blood

Alkaline phosphatase activity is determined by various methods and at different temperature conditions of sample incubation. Above are the standards established by the optimized test at a temperature of 37°C 98 – 279 U/l (for 30°C there is a conversion factor). However, the reader, in search of normal values, may encounter indicators of alkaline phosphatase activity that differ significantly from each other. To avoid confusion and unnecessary worry, it is recommended to use reference values, which are indicated on the laboratory test form and help to understand whether the results obtained are within the normal range or not. To confirm this, we present to the reader another table of normal values for alkaline phosphatase activity:

Of course, it is not possible to predict what reference intervals the reader will find on the Internet or other sources, but he should know the main thing - it is better to ask the laboratory performing the analysis about the range of normal values.

Increased alkaline phosphatase activity

In addition to the physiological reasons for increased enzyme activity (stages of bone tissue formation and development, loss of microelements during pregnancy), an increase in ALP levels in the blood (serum) causes a large number of pathological conditions:

Thus, the reason for the increased activity of alkaline phosphatase is the increased secretion of isoenzymes into the patient’s blood: liver enzyme with changes in the liver parenchyma, biliary tract - with cholestasis, intestinal isoenzyme - with various inflammatory diseases of the gastrointestinal tract, bone - with metastatic lesions of the skeletal system, placental - with pregnancy, tumor processes.

Decreased secretion of isoenzymes (phosphatase is reduced)

A decrease in the release of isoenzymes into the blood leads to lower values of alkaline phosphatase. Basically, this is due to a violation of phosphorus-calcium metabolism, only in the other direction. Alkaline phosphatase is low in the following cases:

Bone destruction caused by very old age (everyone knows about the development of osteoporosis in old people);
Reduced secretory function of the thyroid gland (myxedema);
Accumulation of radioactive isotopes in bone tissue;
Severe anemia;
Lack of ascorbic acid (scurvy);
An excess of vitamin D, usually resulting from excessive, uncontrolled use of dosage forms of the drug prescribed to children for the prevention of rickets.

Not to be confused with acid phosphatase

In addition to alkaline phosphatase, another indicator can be found in a biochemical blood test - acid phosphatase, the prostatic fraction of which serves as an important diagnostic indicator of prostate pathology, since it increases with tumors of this male organ. A particularly sharp increase in the level and activity of acid phosphatase is typical in cases of metastatic growth of cancer of a given localization.

Specific acid phosphatase (prostate phosphatase) is an isoenzyme that is known as prostate-specific antigen or tumor marker PSA (PSA).

Total acid phosphatase noticeably increases its activity during cancer processes localized in the prostate gland. A sharp increase in CF due to the prostatic fraction eloquently indicates the movement of the neoplastic process outside the gland capsule, that is, the spread of metastatic foci to other organs.

Due to the fact that the enzyme is present on blood platelets - platelets and is released in accordance with their activation, a decrease in CP activity in thrombocytopenia of various origins becomes understandable.

A few words about “our little brothers”

Alkaline phosphatase testing is a common test in veterinary medicine. Dog breeders and cat lovers may more often look for the significance of this enzyme in animals than in people, because breeding and preserving a breed is an important and difficult matter, although some of the population is skeptical about such experiences. But dogs also get rickets (and a purebred dog needs to have a healthy skeletal system), they are plagued by diseases of the liver and gallbladder, just like people, “our little brothers,” are affected by malignant tumors.

Meanwhile, one should not equate the normal values of biochemical parameters of the human population with those of animals. Dogs and cats may have different norms, which will be known to a specialist in this field. The norm for alkaline phosphatase in dogs according to some sources is 24 – 85 U/l, while others allow a wider range of values (from 0 to 150 U/l). What kind of analysis a particular dog has, whether it is good or bad, needs to be found out in the laboratory that performed the test (different methods, reagents and reference values).

Elevated alkaline phosphatase: causes and treatment

Alkaline phosphatase is elevated - the causes of this condition can only be determined after a thorough examination. An increase in level often indicates pathological processes occurring in the body.

But first you need to find out what it is, what are the normal indicators and what do they depend on? Are there specific symptoms and what are the reasons for their manifestation? What can laboratory tests tell us?

Meaning and indicators of the norm

Alkaline phosphatase is the most important enzyme present in the cells of all internal organs and takes part in metabolic processes. It is the main element in the exchange of phosphorus and calcium, producing the elimination of phosphate molecules in organic compounds.

The highest activity of the enzyme was observed at the pH present in the human body.

Depending on the location of the enzyme, several types are distinguished:

liver or hepatobiliary phosphatase (ALPL-1);
ostase (ALPL-2);

The level of the indicator in the blood is determined using a biochemical analysis. However, the indicators will be general, not divided by type. There are methods for determining the amount of each individual enzyme, but they are used extremely rarely. When making a diagnosis, specialists use general diagnostic data and the clinical picture of the disease. These factors are sufficient to make a diagnosis.

Normal levels of alkaline phosphatase concentration tend to vary depending on the age of the person. In children, alkaline phosphatase in the blood will be increased compared to adults. During the growth and development of a child, this enzyme takes an active part in the formation of the skeleton and the growth of internal organs.

Therefore, average indicators indicating the norm are interpreted as follows:

children under one year old - no higher than IU/l;
from 1 to 3 years – up to 280 U/l;
from 4 to 6 years – up to 270 U/l;
from 7 to 12 years – up to 300 U/l;
girls from 13 to 17 years old – up to 185 U/l;
boys from 13 to 17 years old – up to 390 U/l;
women -U/l;
men -U/l.

It is necessary to take into account the method used by a particular laboratory to conduct research. Values may vary. When deciphering the analysis result, the reference values required in the standard form are taken into account.

Symptoms and preparation for a blood test

An increase in alkaline phosphatase may be asymptomatic in the early stages or not make itself felt by any specific signs.

However, there are a few to pay attention to:

Nausea, sometimes leading to vomiting.
Decreased or complete absence of appetite.
General fatigue and weakness.
Discomfort, heaviness, nagging or aching pain on the right under the ribs.
Pain in joints, “twisting” of bones.

These symptoms occur in many diseases, but a blood test will help determine ALP in the blood. If necessary, additional studies will be ordered to establish an accurate diagnosis.

An absolutely healthy person may experience an increased level of the indicator in the following cases:

excessive alcohol consumption, which can lead to alcohol intoxication;
taking certain medications that have hepatotoxic side effects;
pregnancy, especially the third trimester.

From this we can conclude that a blood test to determine the level of phosphatase requires preparation:

before collecting biomaterial (venous blood), do not eat for at least 8 hours;
do not drink alcohol even in small quantities and even low-alcohol drinks 2-3 days before the test;
Do not smoke for at least an hour before donating blood;
limit physical activity and sports during the day.

Reasons for increased ALP levels

There are various reasons for increased alkaline phosphatase in the blood. They are physiological and pathological.

Let's consider natural factors that can increase the rate:

Growth, development and sexual changes. In women, this condition occurs before the age of 20, in men – up to 30 years. High (in certain areas) enzyme content decreases spontaneously after the completion of the processes of formation and growth of skeletal bones.
Late pregnancy; the expectant mother's enzyme levels are higher than normal due to active growth of the placenta (placental alkaline phosphatase is detected).
During the recovery period after surgery or healing of fractures. The enzyme will increase, in particular ostase, as bone tissue is renewed.
Taking medications that have a negative effect on the liver. Antibiotics, paracetamol, aspirin, some contraceptives and other drugs that have a hepatotoxic effect have this effect. Long-term use can cause irreparable damage to the liver.
Age indicators also influence the level of alkaline phosphatase. In a growing child, in a woman during menopause, and in older people when bone mass decreases, the concentration of the enzyme increases.
Addictions: smoking, drinking alcohol.
Physical inactivity, lack of physical activity.
Unhealthy diet, oversaturated with fatty, fried and spicy foods, frequent consumption of fast food.
High body mass index, obesity.

Increased alkaline phosphatase occurs in certain pathologies.

Significantly elevated alkaline phosphatase occurs in the following cases:

Cirrhosis is the replacement of healthy liver tissue with scar tissue.
Hepatitis causes the enzyme to increase significantly.
Tumor processes, often malignant, of the organ itself. Metastasis of cancer of various localizations to the liver.
Primary sclerosing cholangitis is a rare liver disease characterized by inflammatory processes that cause liver failure and dysfunction.
Cholestasis is stagnation of bile in the gallbladder, biliary tract and its accumulation in the organ.
Infectious mononucleosis. A blood test will show not only elevated alkaline phosphatase, but also changes in the overall blood picture.
Cholelithiasis.

If alkaline phosphatase is elevated, then bone tissue undergoes the following changes:

Paget's disease is a pathology that damages the repair mechanism in the bones. This leads to weakening and destruction of bone tissue.
Osteomalacia is a systemic pathology characterized by softening and deformation of skeletal bones. Mineral metabolism is disrupted, which leads to excessive excretion of important elements.
Osteogenic sarcoma is a malignant tumor that arises and develops in bone tissue.
Metastasis of cancer of various etiologies into bone tissue.

Other diseases characterized by increased concentrations of alkaline phosphatase in the blood:

endocrine disorders, in particular the thyroid gland. One of the diseases most common in such cases is called hyperparathyroidism. There is a failure in metabolic processes involving phosphorus and calcium.
pre-infarction conditions and the heart attack itself.
ulcerative colitis.
intestinal diseases.

Statistics say that almost 60% of the increase in alkaline phosphatase occurs due to liver damage.

ALP in children

The concentration of the indicator in children is much higher. This is due to the active growth and development of the child.

But sometimes even such a high figure can be exceeded many times over, which indicates the presence of serious pathologies in the child’s body.

liver pathologies, which are characterized by stagnation of bile and insufficient secretion of it into the duodenum;
rickets. When this disease occurs, the ALP indicator plays a key role for early diagnosis and initiation of treatment - the level increases long before obvious signs of the disease appear;

infectious mononucleosis, which in childhood can be asymptomatic, but cause serious complications;
intestinal infection, which in its manifestations is similar to a cold, but requires a completely different approach to treatment;
bone pathologies, including malignant neoplasms;
congenital pathologies and diseases that threaten to develop into a chronic form.

Something about treatment

Before we talk about the measures you need to take to reduce your phosphatase levels, there is something else you need to pay attention to.

Alkaline phosphatase has a clear corridor of normal limits. We already know enough about increasing the level and activity. But could this be a low level and why is it dangerous?

To be fair, it should be noted that a decreased level of the enzyme is a fairly rare phenomenon, but is evidence of a pathology no less serious than an increased one.

The reasons for the decrease may be the following conditions:

transfusion of a large volume of blood or its preparations;
pathologies of the thyroid gland caused by inhibition of its functions;

severe anemia of various etiologies;
deficiency of microelements: magnesium, zinc, calcium, phosphorus and some others;
hypophosphatasia is a congenital pathology that leads to softening of the bones;
if a decrease in alkaline phosphatase is diagnosed during pregnancy, this may indicate placental insufficiency.

If a biochemical analysis reveals an increase in alkaline phosphatase, which is significantly higher than normal values, you need to seek qualified help. If necessary, the local therapist will refer you to a specialist doctor who will clarify the diagnosis and prescribe adequate therapy.

No one can give universal recipes for reducing or increasing enzyme levels. It is not the symptom that needs to be treated (in this case, it is the concentration and activity of ALP that will be a symptomatic indicator), but the cause itself, that is, the disease.

Alkaline phosphatase is an informative criterion in a biochemical blood test. In some cases, increased levels are observed long before clinical symptoms appear. And if we talk about such indicators in children, then treatment of rickets in the early stages leads to complete relief from the pathology, eliminating all consequences.

I think I take pretty good care of my health. I get tested regularly. I just recently took a biochemical blood test and became interested in the question: what is this alkaline phosphate? It was interesting to read and see information on this issue. It's educational.

Elevated alkaline phosphatase does not always indicate disease. Therefore, it is important to find a good specialist so that you don’t start treating something that doesn’t exist.

An increase in alkaline phosphatase in the blood can cause both physiological changes in the body and serious diseases. What are the symptoms of an increase in this enzyme and how to behave when receiving such an analysis?

Symptoms

In the early stages, changes in liver metabolism and the associated increase in alkaline phosphatase levels go unnoticed by the patient. Over time, the body gives signals about a change in condition. The first signs are the following symptoms:

Nausea;

Decreased appetite;

Fatigue and tiredness;

Weakness throughout the body;

Aching pain under the right rib;

Pain in bones and joints.

A similar clinical picture is characteristic of many diseases; a biochemical blood test will accurately determine the level of alkaline phosphatase, but this will only direct the diagnostic search in the right direction. There are many diseases that occur with increased alkaline phosphatase.

Preparing and conducting analysis

Alkaline phosphatase can also be elevated in healthy people. Such cases include:

Consumption of alcoholic beverages that caused alcohol intoxication of the body;
Pregnancy, last trimester;
Medicines with hepatotoxic side effects.

What does it mean? First of all, before taking the test, you need to take measures to prepare the body. This is the only way to trust the results obtained. Such events include:

Abstinence from food for at least 8 hours;
Elimination of alcohol and alcoholic beverages from food consumption for 2-3 days;
Do not smoke 30 minutes before handing over the biomaterial;
Avoid physical strain, including sports, 24 hours before.
If you cannot stop taking medications, then you should inform the medical professional who takes the test. The attending physician should also be notified.

Blood will be taken from a vein for testing.

What causes the enzyme levels to increase?

The causes of elevated alkaline phosphatase may be natural or pathological.

Natural causes include:

Physiological characteristics of the body characteristic of a certain period of life (pregnancy);

An increase associated with external influences on the body (diet, physical activity, medication).

Alkaline phosphatase is elevated - reasons that relate to the physiological characteristics of the body:

Growth, development, and puberty provoke an increase in alkaline phosphatase. When a certain age limit is reached, the level of enzyme in the blood begins to spontaneously fall. Moreover, the female body reaches this mark much earlier (up to 20 years) than men (up to 30 years);

Before birth, the baby in the womb develops and grows more actively. This process causes an increase in the concentration of placental alkaline phosphatase in the blood of the expectant mother;

In the postoperative period or during the recovery period after significant fractures;

Medicines have different effects on the body. There are medications whose long-term use increases alkaline phosphatase. These drugs include: antibiotics, contraceptives, paracetamol, aspirin, drugs with hepatotoxic effects;

Bad habits: smoking, alcohol;

Age characteristics. Children during the period of active growth have increased concentrations of enzymes in the blood. A similar situation is observed in women during menopause. In older people, bones become lighter and more brittle, and their blood alkaline phosphatase levels are higher than normal;

lack of physical activity;

Obesity;

Incorrectly selected diet. The menu is dominated by fatty, spicy and fried foods.

The level also increases with pathological changes in the cells of the placenta, liver, and bones. In order for enzyme molecules to enter the blood, liver and bone cells must be destroyed.

Pathological processes, the symptom of which is high alkaline phosphatase, can be divided into 3 categories:

Liver dysfunction and biliary tract problems. Such ailments include:

Viral and autoimmune hepatitis. Increase in alkaline phosphatase level approximately 3 times;

Cirrhosis. With the biliary type of the disease, the level of alkaline phosphatase can increase 4 times and remain at the reached limit;

Infectious mononucleosis;

Sclerosing cholangitis is a chronic autoimmune disease that causes high pressure in the portal vein area;

Stagnation of bile;

Blockage of the bile ducts with stones. As a result, the outflow of bile is produced in small quantities or there is no exit at all.

Bone diseases:

Severe destruction and deformation (Paget's disease);

Cancer with metastases in bone tissue;

Osteomalacia is a systemic skeletal disorder in which the bone becomes deformed and soft. As a result, phosphoric acid, vitamins and calcium are excreted, and the bones of the skeleton soften;

Osteogenic sarcoma - a tumor forms and develops directly deep in the bone tissue;

Rehabilitation after fractures;

Diseases of a different nature:

Heart attack;

Ulcerative colitis is a chronic inflammation of the colon mucosa;

Intestinal perforation is a through hole in the large intestine through which intestinal contents enter the abdominal cavity;

Hyperparathyroidism is pathological changes in the endocrine system that provoke intensive work of the parathyroid glands.

According to statistics, 50% of cases with high concentrations of alkaline phosphatase were caused by liver disease.

Features of increase in adults

There are a number of nuances that need to be taken into account when deciphering the results of an alkaline phosphatase blood test. First, in men the content of isoenzymes in the blood is always higher than in women. The difference is approximately 20-25 points. With age, the amount of alkaline phosphatase increases in everyone. This means that the concentration of this element depends on the age and gender of the person.

The most popular natural causes of high blood enzyme levels in adults are:

The list of possible reasons for increased levels in women is supplemented by the following “moments”:

Pregnancy, the period before the birth of a baby;
Breast-feeding;
Climax;
Taking hormonal contraceptives. With long-term use, complications in the form of diseases are possible, for example, cholestatic jaundice and intrahepatic cholestasis.

Men over 50 years of age are at risk. They are more likely to develop Paget's disease (skeletal deformity).

High concentrations of ALP in children

Alkaline phosphatase in the blood of children is several times higher than in adults. This situation is explained by the active growth and development of children. The highest concentration will remain until the transition to adolescence. It is at this time that the body produces hormones that affect all metabolic processes.

Despite the high level, when the baby gets sick, alkaline phosphatase can increase several times more for pathological reasons, for example:

Liver diseases in combination with stagnation of bile or its excretion into the duodenum in insufficient quantities;

Rickets. Thanks to ALP, rickets can be detected long before symptoms appear;

Infectious mononucleosis is a disease that can lead to serious complications;

Diseases affecting bone tissue;

Intestinal infection.

More complete information in our article.

Treatment

An increase in the enzyme in medicine is considered as a symptom, but not as a separate disease. At the moment there is no clearly developed course for normalizing the level, since this is impossible. It is necessary to determine the cause and, based on the information received, select treatment.

When diagnosing, it is important to consider that there are a number of natural factors that increase the concentration of ALP even in completely healthy people. Therefore, if necessary, the attending physician prescribes additional studies.

After studying the results of the examination, conducting an examination and collecting an anamnesis, the therapist refers the patient for consultation to specialists of a narrower profile. This could be an endocrinologist, surgeon, oncologist or orthopedist.

Alkaline phosphatase is a hydrolysis enzyme that removes phosphate from various types of molecules. Such molecules can be nucleotides, proteins, and alkaloids. This enzyme is most active in an alkaline environment.

The enzyme ensures the transport of phosphorus through the thickness of cell membranes of cellular structures. The amount and activity of the enzyme is an indicator of the activity of phosphorus and calcium metabolism. Alkaline phosphatase is contained in bone tissue, gastrointestinal mucosa, liver hepatocytes, renal tubule cells; in addition, this enzyme is synthesized in the cells that make up the tissues of the placenta during the period of gestation. The main amount of phosphatase in the human body is found in the small intestine. For example, the concentration of the compound in the mucosa of the small intestine is 30-40 times higher than in liver tissue cells. The compound is synthesized by the surface layer of the small intestinal mucosa, but the role of phosphatase in digestion processes is secondary. The main functions of this compound are to ensure the processes of general metabolism.

To diagnose various ailments, an examination is carried out for the presence and amount of enzyme in body fluids, which are:

blood serum;
urine;
gastric juice.

Additionally, phosphatase isoenzymes are determined:

hepatic;
bone;
intestinal;
placental and some others.

Chemically, the enzyme is an isoenzyme, phosphohydrolase of orthophosphoric acid monoesters. These monoesters have molecular weights ranging from 70 to 120 kDa.

Isoenzyme content in blood serum

Serum alkaline phosphatase levels can vary widely. These indicators range from 44 to 147 IU/l. In this case, when determining the amount of phosphatase in the blood, attention should be paid to the gender of the patient from whom blood was taken for research, and additional attention should be paid to the age of the person being examined. In pregnant women, as a rule, the concentration of alkaline phosphatase in the blood is elevated. Adolescent children who are going through puberty also have a slightly higher rate. An increase in enzyme concentration during this period is not an indication of the presence of any disorders or abnormalities in the body. The reasons for the increased level of alkaline phosphatase in the blood during this period are the rapid processes of its restructuring in the body, which are associated with various life support systems and the growth of bone tissue and the placenta.

As a rule, the content of alkaline phosphatase may fluctuate depending on the reagents used in the research process. At the present stage, there is no standardized laboratory medical method for determining the enzyme. The norm in women and men, depending on the determination method, may fluctuate, but the range of discrepancies in the indicators is insignificant. Alkaline phosphatase is elevated if its concentration exceeds:

in children under 10 years of age the rate is 150-350;
in adolescents from 10 to 19 years of age the indicator is from 155 to 500;
for an adult under 50 years of age, the figure is from 85 to 120;
at the age from 50 to 75 years the indicator is 110 -135;
for a person over 75 years old the figure is 165-190.

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To determine the amount of this type of compound, any specialist conducts a series of clinical studies. However, the boundaries of normal phosphatase levels are broad and depend on a large number of factors, so it is impossible to judge the presence or absence of a particular disease in a person based only on one indicator of the amount of this compound in body fluids. This indicator is used as an additional sign for diagnosing body ailments.

Increasing enzyme concentration in the body

A blood test for low or high alkaline phosphatase is performed for certain medical reasons. This indication could be:

Blood is taken for analysis during liver function tests and to assess the functional capacity of the liver.

Very often, the patient is examined for abnormalities in the amount of enzyme in the blood, if the patient complains of fatigue, loss of appetite, nausea and pain in the right hypochondrium. As an additional diagnostic sign that makes it possible to identify the presence of a disease, the amount of enzyme in the blood serum is determined if there is a suspicion of the development in the body of diseases associated with damage to bones and bone tissue.

An increased level of phosphatase in the serum always signals possible damage or involvement in the pathological process in the body of the bones, liver or biliary tract. An additional set of examinations can be used to clarify the results of the examination. So, for example, if, along with an increase in the concentration of alkaline phosphatase, an increase in the amount of ALT and AST is detected, then this signals the presence of ailments associated with disturbances in the functioning of the liver. If an increase in the amount of the enzyme occurs in conjunction with an increase in the level of calcium and phosphorus, then this indicates the presence of damage to the bone tissue.

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Reasons for increased phosphatase concentrations

Today, medicine knows many reasons that contribute to an increase in the concentration of the enzyme in the patient’s body. The whole range of reasons can be divided into four main groups.

The first group is causes associated with the occurrence of disturbances in the functioning of the kidneys or diseases affecting these organs. Such ailments may be obstructive jaundice, which is caused by obstruction of the bile ducts and the formation of stones in the bile ducts. This disease can be caused by the formation of scars after surgery. Additionally, an increase in the concentration of the enzyme can provoke the development of cancer of the head of the pancreas, stomach, or the formation of cancer metastases in the liver tissue. With hepatitis and cirrhosis of any origin, an increase in phosphatase is detected in the human body. Infectious mononucleosis can be a direct cause of disturbances in the functioning of the liver and can provoke an increase in the amount of enzyme in the blood serum.

The reasons belonging to the second group are disorders associated with the functioning of the bone tissue of the body. These disorders can be provoked by diseases such as osteomalacia, which is a process of softening of bone tissue resulting from a lack of calcium in the body, osteosarcoma, metastases of cancerous lesions that affect the bone tissue of the body, the occurrence of fractures, the development of rickets and myeloma.

The third group represents other reasons not listed in the first two groups. An upward change in the amount of enzyme in the blood may be associated with the occurrence and development of myocardial infarction, ulcerative colitis and the occurrence of intestinal perforation. Additionally, this group includes hyperparathyroidism, which is a hormonal disease that promotes the leaching of calcium from bone tissue.

The causes included in the fourth group are not a consequence of the development of diseases in the body, but they are caused by a whole complex of different factors. This group includes such conditions of the female body as the period of childbearing, adolescence, women under 20 years of age and men under 30 years of age.

Reasons for decreased phosphatase concentration

carrying out large-volume blood transfusions;
decreased functionality of the thyroid gland;
severe anemia;
lack of microelements such as zinc and magnesium in the body;
hypophosphatasia, which promotes softening of bone tissue.

If a decrease in the volume of phosphatase in the blood serum of a pregnant woman is detected, this may indicate insufficient functioning of the placenta.

In order to qualitatively evaluate the result obtained from a quantitative test for alkaline phosphatase, a specialist conducting an examination of the patient’s body needs to conduct a number of studies that can confirm or refute the alleged diagnosis. The quantitative indicators of the enzyme can vary over a wide range, therefore, it is impossible to establish an accurate diagnosis only by studying the amount of enzyme in the blood serum. This indicator can be used in diagnostics to obtain complete information about the patient’s disease.

Analysis of small intestinal juice for alkaline phosphatase and the development of hypophosphatasia in the body

Determination of enzyme activity in intestinal juice is used when assessing the functional state of the gastrointestinal tract and intestinal mucosa. During the study, enzyme activity is determined separately in the duodenum and jejunum. The concentration of the enzyme in duodenal juice can range from 10 to 30 units/ml. People living in southern regions have higher enzyme activity than people living in northern latitudes. Enzyme activity in jejunal juice ranges from 11 to 28 units/ml.

Normal phosphatase activity is considered to be between 10 and 45 U/mL. An increase in enzyme activity to values from 46 to 100 units/ml is classified by doctors as weak. An increase in activity from 101 to 337 units/ml is considered significant. At values exceeding 337 units/ml, this increase in activity is sharp. Enzyme activity depends largely on the type of nutrition, which makes this indicator less informative.

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Hypophosphatasia is a rarely progressive metabolic disorder of hereditary origin. Develops due to alkaline phosphatase deficiency. The deficiency occurs as a result of mutation of the gene that encodes a nonspecific tissue enzyme. The lack of activity of a nonspecific enzyme in the patient’s blood serum provokes the development of hypomineralization in the body and extensive disturbances in the processes of mineral metabolism in bone tissue; in addition, such an anomaly provokes the development of multiple organ complications in the patient’s body.

At the moment, there is no method for treating this disease in medical science, and the only medicine that can stop the development of the disease in the human body is the promising enzyme-containing drug Phosphatase alpha.

The article discusses the situation when alkaline phosphatase is elevated, what are the reasons, what does this mean, what is the norm of alkaline phosphatase in women and men. As well as the reasons for its decrease and features of the analysis.

ALP in biochemical analysis is a standard laboratory indicator. The need for research is determined by the attending physician. It is possible to measure the parameter as part of an extended biochemical study or isolated.

It is worth noting that information about the value of the parameter in question is not enough to establish a specific diagnosis. However, the data obtained are used for the primary diagnosis of organs in which alkaline phosphatase is localized (liver tissue, bone tissue, placental tissue, etc.).

ALP is a protein enzyme involved in the reaction of detachment of phosphoric acid salts from molecules. Preferred locations are the liver, bone tissue and bile ducts. It enters the systemic bloodstream during the destruction and death of cells of these organs, while losing its enzymatic activity. Large-scale cell death leads to the release of the enzyme from them, as a result of which a person experiences an increase in alkaline phosphatase levels.

It is noted that the substance in question reaches peak activity under alkaline conditions. Therefore, with the active accumulation of bile, the enzyme activity increases.

The site of ALP formation is young bone tissue cells. Accordingly, enzymatic activity is a characteristic sign of the active functioning of these cells. Young bone cells are essential for bone formation and renewal. Based on this, after a fracture in people they begin to be actively synthesized, which means they lead to the active production of alkaline phosphatase.

Alkaline phosphatase test - when and how to take it?

The study is necessary to diagnose pathologies affecting the liver, musculoskeletal system and bile ducts. The laboratory criterion under consideration is measured when clarifying the fact of the spread of cancer pathology in human bones. Since malignant neoplasms lead to increased growth of bone cells, and hence alkaline phosphatase.

Repeated tests are necessary to determine the effectiveness of the chosen treatment strategy. The lack of positive dynamics of the disease indicates the need for correction of the selected therapeutic methods.

Symptoms for which it is necessary to check the level of the laboratory criterion in question:

chronic fatigue;
decreased appetite;
the appearance of yellowness of the skin;
digestive problems;
hyperemia of the palms (palmar erythema);
cloudy or discolored urine or stool;
redness and itching, unknown etiology;
pain in the bones or abdominal area;
frequent fractures.

In addition, the study is part of a set of mandatory procedures when preparing a person for surgery.

Rules for preanalytical preparation for the patient

For proper preparation, you must follow 3 rules:

refuse food for 8-12 hours before taking biomaterial;
do not drink alcohol the day before the test;
avoid physical or emotional stress 1 hour before the laboratory visit;
do not smoke 30 minutes before venipuncture.

It is necessary to obtain venous blood serum as a biomaterial for analysis. When establishing the level of the substance in question, the kinetic colorimetric method is used. Its essence lies in assessing the change in color intensity of solutions used for laboratory analysis.

The normal level of alkaline phosphatase in the blood of women

To understand when an increase in alkaline phosphatase is detected, we will first consider the options for its permissible (reference) values. Before the onset of large-scale hormonal changes during puberty, the value of the criterion in both sexes does not have pronounced differences. After the onset of puberty, normal ALP values for girls and boys should be determined individually. Therefore, up to 13 years of age, the values indicated in the table apply to both sexes, after - only to women.

Particularly high values of the indicator are typical for the baby’s first year and for the puberty period. This fact is explained by increased growth and renewal of bone tissue. After final puberty, the level should not exceed 150 U/l.

During pregnancy, the level of the enzyme in question increases slightly. Because it is found in the cells of the placenta of the developing baby.

Alkaline phosphatase levels in men

Acceptable criterion values for boys (under 13 years of age) are identical to women’s values. Let's take a closer look at the reference indicators for boys starting from 13 years old.

What does it mean if alkaline phosphatase is elevated in the blood of an adult?

Important: an increase in alkaline phosphatase does not always indicate the presence of disease in a person. In order to establish the cause, it is necessary to conduct a comprehensive examination using additional laboratory and instrumental diagnostic methods. Let us consider the main reasons for the criterion to go beyond normal values.

Liver

The first reason is liver disease. For example, jaundice, which occurs as a result of blockage of the bile ducts. Bile begins to be actively deposited, creating an alkaline environment. It is here that the maximum activity of the enzyme is observed.

A similar condition is typical for malignant lesions of the bile ducts, as well as the pancreas, liver or stomach.

A threefold excess of the norm is typical for hepatitis of various etiologies. A significantly lower excess is typical for liver cirrhosis. With this pathology, healthy organ tissue is actively replaced by scar tissue, which causes inhibition of its normal functioning.

With monocytic tonsillitis (infectious mononucleosis), lymphoid tissues and the liver are affected. The disease is viral in nature (cytomegalovirus or Epstein-Barr virus)

It is extremely rare that autoimmune pathologies such as primary biliary cirrhosis and primary sclerosing cholangitis become the cause of changes in the level of alkaline phosphatase. Patients have critically high values of alkaline phosphatase and gamma-lutamyltransferase.

Bones

The second reason is diseases of the scythes.

15 - 20-fold excess of the indicator is characteristic of Paget's disease. The pathology is characterized by increased degradation of bone tissue, which naturally leads to deformation and frequent bone fractures. According to statistics, pathology is more often diagnosed in patients over 50 years of age. In younger people it is extremely rare.

The course of the disease is not accompanied by typical symptoms at an early stage. The disease can be suspected by examining x-rays and detecting a significant increase in alkaline phosphatase in the biomaterial being studied. Currently, there are no methods that can lead to complete relief from this pathology. However, maintenance therapy provides patients with a comfortable life.

Sarcoma of bone tissue has a dangerous, pronounced malignant course. The pathology has the highest rates of spread and formation of metastases. The majority of identified cases occur between the ages of 12 and 35 years, with the predominant manifestation of the disease at the end of puberty. In women, it is diagnosed 2 times less often. Most often, sarcoma is found in long bones.

The modern level of medicine allows patients with sarcoma to increase their life expectancy. In 80% of cases, a person manages to save the affected limb. The average patient survival rate reaches 90%.

Osteomalacia is another cause of increased ALP. The patient has a lack of calcium, which leads to increased bone fragility. The disease is characterized by a favorable course with regular medical monitoring of the person’s condition.

Other reasons

Alkaline phosphatase in the blood increases due to excessive activity of the parathyroid glands. Since the increased content of parathyroid hormone promotes increased excretion of calcium ions. Similar changes are typical for people following an unbalanced diet. Improper diets with insufficient amounts of calcium, phosphorus or vitamin D contribute to the need for active bone tissue synthesis.

A temporary increase in the indicator is typical for fractures and mechanical damage to bones. To restore the affected areas, the body begins to actively synthesize young bone cells.

A change in the indicator is detected in pathologies of the gastrointestinal tract. Because some amount of alkaline phosphatase is contained in the intestinal cells.

False-positive results are detected when the taken biomaterial is stored incorrectly. Thus, cooling the biomaterial immediately after collection causes an increase in the indicator. Therefore, it is important to observe the time interval (30-45 minutes) for keeping the tube after venipuncture at room temperature for clot formation.

Medicines that increase the value of the criterion under consideration: analgesics, antipyretics and antibacterial agents, large doses of vitamin C. When taking them, it is important for the examined patient to notify the employee of the laboratory department.

What does it mean if alkaline phosphatase is low in the blood?

Alkaline phosphatase is reduced in women taking combined oral contraceptives. This must be taken into account when selecting reference indicators. A similar situation is observed after taking biomaterial for analysis after a recent transfusion of a large amount of blood.

Lack of the enzyme is characteristic of a severe stage of anemia and thyroid dysfunction in a patient. A lack of magnesium or zinc ions also causes a decrease in the laboratory criterion.

It is extremely rare for people to develop congenital hypophosphatization, which poses a serious threat to the patient’s life. It manifests itself in the form of an abnormal process of bone mineralization and severe pathologies of the respiratory system.

In pregnant women, a lack of the enzyme is a sign of fetoplacental insufficiency. This requires extensive diagnostics of the patient and selection of the necessary treatment methods.

To exclude false negative results, it is important to follow the rules for storing blood serum. Thus, an error in choosing a transport tube (the presence of citrate, EDTA, arsenic or manganese in it) will lead to inhibition of enzyme activity. What will cause unreliably low indicators?

Combined deviation of laboratory criteria

Alkaline phosphatase is elevated - the causes of such changes are quite varied and can affect several organs. The results of an isolated study on one parameter are not enough for the attending physician to determine the exact cause. To fully consider the topic, it is necessary to understand what the combined changes in laboratory parameters together with alkaline phosphatase indicate?

If abnormalities in the level of alkaline phosphatase, bilirubin, alanine aminotransferase and aspartate aminotransferase are detected, liver damage is suspected.

If a combined change in alkaline phosphatase, calcium and phosphorus ions is detected, the likely cause is bone pathology.

A simultaneous increase in gamma-glutamyl transpeptidase along with alkaline phosphatase is a sign of blockage of the lumen of the bile ducts.

It should be emphasized that a change in this indicator up or down indicates damage to the liver, bones or bile ducts. Other organs - in fairly rare situations.

conclusions

To summarize, the main points of the article should be highlighted:

when liver and bone tissue cells are damaged, alkaline phosphatase is fixed in excess amounts in the blood. Since it is predominantly localized in these organs;
Exceeding the reference values by the criterion in pregnant women is a variant of the physiological norm. Since this enzyme is found in the cells of the placenta;
medications affect the value of the indicator, so their use must be reported to the laboratory;
It is important to follow the rules of preanalytical preparation for blood collection. The reliability of the data obtained largely depends on this. Cooling of the taken biomaterial is not allowed;

Today, laboratory examination methods are used in the complex diagnosis of many diseases. In this case, a biochemical blood test is performed.

Alkaline phosphatase: general characteristics of the enzyme

Alkaline phosphatase is one of the important indicators. This compound is an enzyme that exhibits phosphatase activity. It is present in almost all cells of the human body. Its maximum activity occurs in an alkaline environment and is associated with cell membranes. The highest concentration of this compound is recorded in osteoblasts (cells in the cells of the liver and kidney tubules, in the intestinal mucosa, as well as in the placenta. Alkaline phosphatase, which is found in blood serum, usually comes from bone tissue or hepatocytes. Its high activity is observed in mainly for liver diseases that occur with obstruction of the bile ducts, as well as for bone lesions that are accompanied by bone tissue remodeling.

Alkaline phosphatase levels are high. Why?

There are many pathological conditions in which alkaline phosphatase increases. The norm of this indicator depends on age and gender, so this is taken into account when interpreting a biochemical blood test.

Among the etiological factors that can affect the level of enzymes, including alkaline phosphatase, the following should be mentioned:

Pregnancy;

The period after menopause;

Insufficient dietary intake of calcium and phosphates;

Excess ascorbic acid in the body;

Use of certain pharmacological drugs (for example, contraceptives containing estrogen and progesterone, as well as antibiotics).

In addition, alkaline phosphatase can be increased in the following diseases:

Hyperparathyroidism;

Infarction of the kidney or lung tissue;

Multiple myeloma;

Infectious mononucleosis;

Bone lesions, including cancerous ones;

Lymphogranulomatosis, which occurs with bone destruction;

Malignant lesion of the biliary tract;

Inflammation of an infectious nature or cirrhosis of the liver, its tuberculosis.

Etiology of decreased alkaline phosphatase

There are a number of pathologies in which, on the contrary, alkaline phosphatase decreases. Thus, the level of this enzyme is lower than normal in hypothyroidism. Impaired bone growth, zinc and magnesium deficiency, and anemia are etiological factors that can affect the amount of alkaline phosphatase in the blood serum. Taking certain medications also changes test results. In addition, the presence of scurvy, which develops due to a deficiency of ascorbic acid, leads to a decrease in this enzyme.

It should be noted that during pregnancy, alkaline phosphatase can increase due to an increase in the amount of placental isoenzyme. This is typical for the final stages of pregnancy and is associated with maximum development of the placenta. This pattern has no diagnostic significance, therefore it is not used to assess the condition of the mother or fetus. In cases where a woman is diagnosed, the concentration of this enzyme compound decreases.

Features of changes in alkaline phosphatase levels

Alkaline phosphatase occurs in the form of several isoenzymes. The degree of increase in the concentration of this compound correlates with osteoblastic activity (with the process of bone formation), therefore the highest level of bone isoenzyme is observed in Paget's disease. If a patient develops pathologies with osteolytic activity (for example, alkaline phosphatase increases, but only slightly.

With lesions, the liver isoenzyme increases. In clinical practice, it is used as a marker of cholestasis. In this case, direct damage to liver cells can occur against the background of normal or even decreased levels of alkaline phosphatase. This pattern is typical, as a rule, for most clinical cases, although it may not be observed in a particular patient, even with damage to the liver or biliary tract.

It is worth noting that alkaline phosphatase is elevated in a child - a physiological phenomenon that is associated with active growth. Thus, the level of this enzyme in childhood can reach a level that exceeds the norm for an adult by 1.5-2 times (from 82 to 341 U/l).

Specifics of determining the level of alkaline phosphatase

Today, the optimal conditions for performing analysis to determine the concentration of alkaline phosphatase are different, since each laboratory has its own standards. There are several research methods that depend on the enzyme substrate and also on the temperature at which the samples are carried out. There are no uniform boundaries for the “alkaline phosphatase” indicator, so you should not compare the values of this enzyme that were obtained in different laboratories. This is especially true in cases where it is not known what standards these laboratories set.

Blood serum is used for analysis. In most cases, the top layer that forms in the separator tube is taken. It is worth noting that alkaline phosphatase levels may be falsely elevated if a tourniquet was applied to the upper extremity for more than 30 seconds during blood sampling. In addition, the activity of this enzyme may change slightly if blood samples are stored at room temperature. In this case, hemolysis in vitro does not affect the results of the analysis.

What to do if there is a pathological level of alkaline phosphatase?

When treatment should have an etiological direction. So, if you have diseases of the liver or bile ducts, you should consult a gastroenterologist. Cholestasis, the presence of pancreatitis, alcoholic hepatitis or cirrhosis of the liver requires appropriate drug correction, the volume of which is determined only by a doctor. Self-medication in this case can lead to exacerbation of the underlying disease.

Changes in the concentration of enzymes, including alkaline phosphatase, can be observed in heart failure, cancer pathologies and severe kidney damage, as well as diabetes, so it is worth consulting with a cardiologist, nephrologist or endocrinologist. The doctor will determine the therapeutic tactics depending on the clinical picture.

When etiological factors are eliminated, alkaline phosphatase activity returns to normal. When prescribing therapy, it should be taken into account that, for example, a physiological increase in this indicator is possible with fractures, active growth of the skeletal system, and during pregnancy. It does not require medical intervention. Interpretation of laboratory test results should be carried out comprehensively, taking into account other biochemical indicators and patient complaints.