This means analysis alt ast. ALT and AST - what they are, the norm and causes of elevated levels in the blood. Standards for adults

Aspartate aminotransferase (AST) is an enzyme that is found in all cells of the body, but mainly in the cells of the heart and liver and to a lesser extent in the kidneys and muscles. Normally, AST activity in the blood is very low. When liver tissue or muscles are damaged, it is released into the blood. Thus, AST is an indicator of liver damage.

Synonyms Russian

Serum glutamine-oxaloacetic transaminase, serum glutamate-oxaloacetate transaminase (SGOT), aspartate transaminase, AST/ALT ratio.

English synonyms

Aspartate aminotransferase.

Research method

UV kinetic test.

Units of measurement

U/L (unit per liter).

What biomaterial can be used for research?

Venous, capillary blood.

How to properly prepare for research?

• Do not eat for 12 hours before the test.
• Avoid physical and emotional stress for 30 minutes before the test.
• Do not smoke for 30 minutes before the test.

General information about the study

Aspartate aminotransferase (AST) is an enzyme that is found in all cells of the body, but mainly in the heart and liver and to a lesser extent in the kidneys and muscles. In healthy patients, AST activity in the blood is low and the AST norm is low. When the liver or muscles are damaged, AST is released and the level of AST in the blood increases. In this regard, the activity of this enzyme is an indicator of liver damage. AST analysis is part of the so-called liver tests - studies that diagnose liver disorders.

The liver is a vital organ that is located in the upper right side of the abdominal cavity. It is involved in many important functions of the body - it helps in the processing of nutrients, the production of bile, the synthesis of many important proteins such as blood clotting factors, and also breaks down potentially toxic compounds into safe substances.

A number of diseases lead to damage to liver cells, which increases AST activity.

Most often, an AST test is prescribed to check whether the liver is damaged due to hepatitis, toxic drugs, or cirrhosis. However, AST does not always reflect only liver damage; the activity of this enzyme can also increase in diseases of other organs, in particular myocardial infarction.

What is the research used for?

• To detect liver damage. Typically, an AST test is ordered along with an alanine aminotransferase (ALT) test or as part of a general liver function test. AST and ALT are considered the two most important indicators of liver damage, although ALT is more specific than AST. In some cases, AST is directly compared with ALT and their ratio (AST/ALT) is calculated. It can be used to find out the causes of liver damage.
• The AST level in the blood is often compared with the results of other tests, such as alkaline phosphatase (ALP), total protein, and bilirubin, to determine the specific form of liver disease.
• To monitor the effectiveness of treatment of liver diseases.
• To monitor the health of patients taking medications that are potentially toxic to the liver. If AST activity increases, the patient may be switched to other medications.

When is the study scheduled?

• For symptoms of liver disorder:
  • weakness, fatigue,
  • loss of appetite,
  • nausea, vomiting,
  • abdominal pain and bloating,
  • yellowing of the skin and eye whites,
  • dark-colored urine, light-colored stools,
  • itching.

• If there are factors that increase the risk of liver disease:
  • previous hepatitis or recent contact with hepatitis infection,
  • excessive alcohol consumption,
  • hereditary predisposition to liver diseases,
  • taking medications that can damage the liver,
  • overweight or diabetes.
  • On a regular basis throughout the treatment process to determine its effectiveness.

What do the results mean?

Reference values ​​(AST norm for men, women and children):

Normally, AST activity in the blood is low.

Excessively high AST activity (more than 10 times normal) is usually caused by viral infections. It can also increase significantly as a result of taking medications or other substances that are toxic to the liver, as well as due to diseases that slow blood flow to the liver (ischemia).

In chronic hepatitis, AST activity usually exceeds the norm by no more than 4 times. It fluctuates between normal and slightly elevated, so an analysis is often prescribed to determine the extent of the disease. Diseases such as bile duct obstruction, cirrhosis, and some types of liver cancer contribute to moderate increases in AST. After a heart attack or muscle damage, AST activity may also increase, usually much higher than ALT.

In most liver diseases, ALT activity in the blood is higher than AST activity, so the AST/ALT ratio will be low. However, there are a few exceptions: alcoholic hepatitis, cirrhosis and muscle damage.



Important Notes

• During pregnancy, AST activity may decrease.
• Intramuscular injections of drugs, as well as intense physical activity, help increase AST activity in the blood.
• In some patients, liver damage and, as a result, an increase in AST activity may be caused by taking dietary supplements. Therefore, it is necessary to inform your doctor not only about all medications you are taking, but also about nutritional supplements.

Who orders the study?

Therapist, cardiologist, hepatologist, gastroenterologist, general practitioner, surgeon, pediatrician.

If a patient has been prescribed blood biochemistry, then he will probably be interested in what the AST indicator is in a biochemical blood test.

What kind of protein is this and how are the results deciphered?

AST or aspartate aminotransferase is an intracellular enzyme that takes part in protein metabolism. It is responsible for the production of amino acids in cell membranes and tissues.

This enzyme is quite unique and allows detection of a fairly narrow range of pathologies.

AST does not manifest itself in all systems of our body; its largest amount is in the heart muscle and liver tissue, muscles, skeleton and neurons of the brain, which are characterized by high activity of metabolic processes.

The enzyme helps the cells of these organs maintain their integrity and structure.

As long as the cells containing AST are not damaged, the volume of protein in the plasma fluid is minimal and within normal limits.

However, if the cells are damaged, the protein enters the blood system in large quantities. In this case, a biochemical blood test detects an increase in AST.

The more actively organ particles are destroyed, the more elevated the protein will be.

In addition, the time of the onset of decay is also reflected in the test results - the longer the process lasts, the less AST will be in the blood.

AST analysis helps specialists detect the process of decay in the myocardium or liver, since when other systems are disrupted, the volume of protein does not increase.

Often, an AST test is prescribed not only to detect damage in these systems, but also to exclude liver or heart diseases.

Indications and preparation for analysis

In accordance with generally accepted standards, blood biochemistry with AST is used to detect many pathologies.

Biochemical analysis will be effective in identifying abnormalities in the heart muscle as a result of a heart attack.

The analysis is also prescribed before complex operations to monitor the condition of the body, after treatment with antibiotics, chemicals and other aggressive drugs, and to evaluate previous treatment of the heart or liver.

In addition, it is possible to identify various pathologies of the blood and heart systems, both chronic and acute, problems with the liver and kidneys, poisoning, infectious diseases, purulent processes, encephalopathy, acute diseases of the abdominal organs, autoimmune diseases, jaundice, metabolic failure bilirubin, cholelithiasis, neoplasms and metastases, trauma to the abdominal cavity and chest with possible bruise of the liver or heart.

A biochemical blood test with AST is taken on an empty stomach, as in most similar studies.

The last meal should be no later than 8 hours before the procedure. It is important to know that the day before the test you should abstain from fatty and fried foods, alcoholic drinks, as well as from playing sports.

You cannot conduct a blood test immediately after an ultrasound, x-ray, FG diagnostics or any physiotherapeutic procedures.

A couple of weeks before the test, the doctor should stop taking medications that the patient is currently taking.

If canceling them is impossible, the doctor must write in the referral a list of the medications the patient uses and the amounts so that the laboratory technician takes this into account.

Alcohol, eating fatty foods, medications and much more can affect the results of the study and distort them, which is why the procedure will no longer be informative and deciphering will be difficult.

Norms and reasons for the growth of AST

In order for the study to be deciphered correctly and the indicators to be correctly interpreted, you need to know what the AST rate is in the blood of a healthy person.

The AST norm in female blood is 31–35 U/L, and the male norm is 41–50 U/L. As for children, up to 1 month the AST norm is 74 units/l, from 2 to 12 months. – 60 units/l, and from one year to 14 years – 45 units.

If the biochemical indicator is elevated, doctors talk about hepatitis, cirrhosis, jaundice, various liver pathologies, oncological processes, angina pectoris, myopathy, pancreatitis and other pathologies.

In addition, the transcript may show an increase in the enzyme after injuries, cardiac interventions, and angiography.

If the studied indicator is noticeably reduced, this phenomenon has no diagnostic power.

If the AST rate in a blood test is increased by 20 to 50 times, then doctors usually suspect hepatitis or liver pathologies with necrosis.

If the protein is increased 2-5 times, then this indicates muscle injuries, pancreatitis, gangrene, and hemolytic problems. With thrombosis of the pulmonary arteries, the enzyme is increased by 2–3 times, and with muscle dystrophy – by 8 times.

If during biochemical analysis the volume of the enzyme is increased, this means the presence of a disease.

The most common causes of increased protein are hepatitis, heart attack at the very beginning of its appearance, heart injury, toxic damage to the liver, intoxication as a result of purulent and septic processes in tissues and organs, chronic heart failure, impaired blood flow in the liver, cirrhosis, metastases and neoplasms, myeloblastic leukemia heart and liver, tissue destruction in muscles.

An increase in AST does not always indicate cell breakdown. A change in the enzyme level by several units is not yet a reason to sound the alarm.

Only if the indicator in biochemistry is increased by two times or more from the norm, then specialists study this problem in detail.

Experts distinguish three stages of increasing AST:

1. moderate – increased five times;
2. average – increased 10 times higher than normal;
3. severe – the norm is exceeded by more than 10 times.
4. ALT as a result of the analysis

During the blood test, specialists compare AST volumes with ALT diagnostics. ALT is an enzyme that is also found in the cells of the liver, kidneys, muscles, heart, and pancreas.

When one of these organs is damaged, the blood is saturated with a large amount of the ALT protein.

The ALT norm in the body of an adult man is 40 units/l, in women – 32 units/l.

You should know that ALT can rise after sports, injuries, long-term use of medications - antibiotics, barbiturates, contraceptives. Protein may also increase in adolescents during periods of active growth.

If the ALT level in the blood is exceeded, the reading may indicate hepatitis and other liver pathologies, since the cells of the organ are destroyed, as a result of which ALT enters the blood system.

Also, a high level of ALT may indicate a heart attack, while both ALT and AST are released into the blood.

The ratio of AST and ALT is the de Ritis coefficient. The norm for this value is from 0.91 to 1.75.

If the coefficient increases to 2 or more, then the decoding shows the breakdown of the heart muscle and the destruction of cardiomyocytes.

If the indicator is below 1, doctors diagnose liver disease: the lower this number, the more likely an unfavorable outcome of the disease.

If you decide to lower the level of protein in the body on your own, you should know that an increase in AST is not an independent disease, so there are no specific ways to reduce the amount of the enzyme in the body.
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An increase in the enzyme indicates the process of breakdown of cells of the heart, muscles, and liver, so you need to carefully examine the organs and find out what disease underlies all these processes.

Only organs with healthy cells will be able to work correctly and at full strength, and biochemical indicators will be as close to normal as possible.

An increase in biochemical parameters is not the root cause of the disease, but its result. If the level of AST or ALT according to the results of a blood test is elevated, you should immediately consult a doctor.

When a person is sick, it is almost impossible to make a correct diagnosis and prescribe competent treatment without tests. Often it is not necessary to undergo all existing laboratory tests. Today, it is enough for a doctor to study the transcript of a biochemical blood test and the normal values ​​of ALT and AST in an adult or child in order to understand the full nature of the disease. One of the most important indicators in this analysis is the level of liver enzymes - ALT and AST. A change in the acceptable limits of these blood components may indicate serious illness.

What is AST

AST, in scientific circles, aspartate aminotransferase is a “builder” protein responsible for the synthesis of amino acids in the body. In addition, he is an active participant in all metabolic processes of the body.

AST is a component that has its own specifics. It is concentrated exclusively in tissues, and detection of it in serum is an alarming sign. The highest concentration of this enzyme is concentrated in cardiac, renal, and muscle tissues, some are located in nervous tissues. As soon as the analysis reveals the presence of this element in the biomaterial, it means that pathology begins where AST is contained most of all. Accordingly, its level in the blood begins to increase. Most often, diseases are associated with pathologies of the heart or liver. All changes in AST levels can only be detected by a biochemical blood test.

A few words about ALT

Together with the AST indicator, a biochemical blood test reveals the level of ALT, alanine transferase - an enzymatic protein synthesized in the human liver. The main percentage of ALT is found in the liver and kidneys, while cardiac tissues contain a small amount.

This enzyme is involved in the metabolism of amino acids. Thanks to this, overall immunity increases, the production of lymphocytes actively begins, and controls the production of sugar. Nature arranges it in such a way that this liver transaminase behaves more actively in the male body than in the female body.

If the level of ALT increases, then most likely we have a problem with the kidneys, liver, lungs or pancreas.

AST and ALT are indicators that are considered and interpreted in conjunction with each other.

Indications for analysis

It happens that to make a diagnosis, the attending physician only needs an analysis of ALT and AST. Biochemistry is prescribed in the following cases:

• pregnancy;
• with existing pathology of the heart and liver;
• control of prescribed therapy;
• suspected cardiac infarction;
• injury to the abdomen or chest;
• when taking potent medications that have a detrimental effect on the heart and liver. For example, in the treatment of HIV or major depression.

What can tests tell you?

AST test and ALT blood test are the most important tests. Any deviation from the norm is considered pathology. AST and ALT monitor the body's response to various stimuli.

From the liver it can be:

1. Liver damage from alcohol or excessive or long-term use of medications.
2. Liver cirrhosis, including alcoholic cirrhosis.
3. Hepatitis of any type

The level of ALAT in the blood can vary depending on the degree of physical stress on the body, the presence of burn areas, ischemic injuries, and any type of injury. Based on the results obtained, the doctor prescribes appropriate treatment.

Rules for collecting biomaterial

Absolutely any analysis requires careful preparation. This is the only way you can be sure of the reliability of the results obtained.

Since ALT and AST are the most important indicators of liver function, it is very important to adhere to a diet for at least a few days before donating biomaterial.

Don't eat salty, fatty, spicy foods. This can not only worsen your indicator, but also increase blood clotting significantly, which may not allow the examination to be carried out as required.

• The analysis is taken strictly on an empty stomach with a fasting pause of 8 hours or more.
• Avoid smoking for at least a few hours before giving your sample.
• Drink only plain water. Sugary drinks will blur the real picture.
• Alcohol is prohibited.
• Limit the consumption of eggs, cottage cheese, and any fermented milk products.
• Avoid physical fatigue on the eve of the test.
• Set yourself in a positive mood, calm down, and only then head to the treatment room.
• You should not analyze the level of AST and ALT if the day before you underwent an ultrasound examination, x-ray, visited a physiotherapy room, or had fluorography.

Interpretation of analyzes

AST. Norm and deviations

In an ideal biochemistry test, the AST reading should be as low as possible. This means that no health problems have been identified to date. However, it is important to understand that norms for this study are a relative concept. They vary depending on age and gender.

Only high levels can be a sign of the disease. We are not talking about a low level of ASAT. Even if you see 0 units/l in the transcript, there is no need to worry. This is not considered a deviation or sign of a disease. The only thing that a decrease in ALT and AST in the blood can indicate is a lack of B vitamins. A decrease in levels is also typical during pregnancy, which is due to bearing a baby and hormonal changes.

Doctors divided the severity of the situation into three types:

• moderate, when the excess is 5 times;
• medium form - 10 times;
• severe form, in which the AST level is increased by 10 times or more.

The following pathologies are possible:

ALT norms

The norms of ALT, like AST, depend on the gender and age of the patient. The study in children is carried out taking into account age.

It is important to realize that all these norms are relative. Thus, the result may be increased when taking certain drugs, for example, aspirin, paracetamol or when using oral contraceptives. The same false result will be given to you by using valerian, echinacea, excessive physical activity due to non-compliance with the rules for submitting biomaterial.

Preliminary diagnosis	Comments
Myocardial infarction	The indicator is increased 5 times; if the increase in level continues, then this is a sign of deterioration of the patient’s condition.
Hepatitis	Increase in norm by 20-50 times. With hepatitis A and jaundice, the increase is insignificant, but appears several weeks before the disease, which makes it possible to block the disease in time. With hepatitis caused by alcohol or a virus, there is no latent period, and the indicators are significantly elevated immediately.
Muscle dystrophy	Increased 8 times
Acute pancreatitis	The indicator is overestimated by 3-5 times. To avoid future attacks, doctors recommend systematically taking tests for ALT and AST.
Liver cancer	Sometimes surgery is required, which is not possible if ALT levels are high.
Myocarditis	Shortness of breath, fatigue, and AST levels increase.
Cirrhosis	The norm was exceeded 5 times.

An increase in ALT may not be associated with pathological processes in the body. This is often due to the following factors:

1. Violation of the norm for the delivery of biomaterial. For example, unwanted alcohol consumption a few days before the test.
2. Taking herbal preparations and any other medications.
3. Unbalanced diet, eating fast foods.
4. Stress
5. Drug use

To make the interpretation of the analysis for AST and ALT as accurate as possible, the Ritis coefficient is used, which shows the ratio of transferases in the blood. Based on its results, a diagnosis is accurately established.

A biochemical blood test is an important study that allows us to evaluate the functional state of organs and systems of the human body by analyzing various microelements in the blood. Below are the components of a biochemical blood test used in the diagnosis of viral hepatitis.

Alanine aminotransferase (ALT, ALT, ALT) is an enzyme contained in tissues in the liver and released into the blood when it is damaged. Elevated ALT levels can be caused by viral, toxic or other liver damage. With viral hepatitis, ALT levels can fluctuate over time from normal values ​​to several normal values, so this enzyme must be monitored every 3-6 months. It is generally accepted that the ALT level reflects the degree of hepatitis activity, but about 20% of patients with chronic viral hepatitis (CVH) with a consistently normal ALT level have serious liver damage. It can be added that ALT is a sensitive and accurate test for the early diagnosis of acute hepatitis.

Blood test AST - astspartate aminotransferase (AST, AST) is an enzyme contained in the tissues of the heart, liver, skeletal muscle, nervous tissue and kidneys and other organs. An increase in AST in a blood test together with ALT in patients with chronic hepatitis may indicate necrosis of liver cells. When diagnosing chronic hepatitis, special attention should be paid to the AST/ALT ratio, called the de Ritis ratio. An excess of AST in a blood test over ALT in patients with chronic hepatitis may indicate severe liver fibrosis or toxic (drug or alcohol) liver damage. If AST in the analysis is significantly increased, then this indicates necrosis of hepatocytes, accompanied by the breakdown of cellular organelles.

Bilirubin is one of the main components of bile. Formed as a result of the breakdown of hemoglobin, myoglobin and cytochromes in the cells of the reticuloendothelial system, spleen and liver. Total bilirubin includes direct (conjugated, bound) and indirect (unconjugated, free) bilirubin. It is believed that the increase in bilirubin in the blood (hyperbilirubinemia) due to the direct fraction (more than 80% of total bilirubin is direct bilirubin) is of hepatic origin. This situation is typical for chronic hepatitis. This may also be due to impaired excretion of direct bilirubin due to cytolysis of hepatocytes. An increase in concentration due to free bilirubin in the blood may indicate extensive damage to the liver parenchyma. Another reason may be a congenital pathology - Gilbert's syndrome. Also, the concentration of bilirubin (bilirubinemia) in the blood may increase when the outflow of bile is obstructed (blockage of the bile ducts). During antiviral therapy for hepatitis, an increase in bilirubin can be caused by an increase in the intensity of hemolysis of red blood cells. With hyperbilirubinemia above 30 µmol/l, jaundice appears, which is manifested by yellowing of the skin and sclera of the eyes, as well as darkening of the urine (urine takes on the color of dark beer).

Gamma-glutamyl transpeptidase (GGT, GGTP) is an enzyme whose activity increases in diseases of the hepatobiliary system (a marker of cholestasis). Used in the diagnosis of obstructive jaundice, cholangitis and cholecystitis. GGT is also used as an indicator of toxic liver damage caused by alcohol and hepatotoxic drugs. GGT is assessed together with ALT and alkaline phosphatase. This enzyme is found in the liver, pancreas, and kidneys. It is more sensitive to disorders in liver tissue than ALT, AST, alkaline phosphatase, etc. It is especially sensitive to long-term alcohol abuse. At least five processes in the liver increase its activity: cytolysis, cholestasis, alcohol intoxication, tumor growth, drug damage. In chronic hepatitis, a persistent increase in GGTP indicates either a severe process in the liver (cirrhosis) or a toxic effect.

Alkaline phosphatase (ALP, AP, Alkaline phosphatase, ALP, ALKP) is used to diagnose liver diseases accompanied by cholestasis. A combined increase in alkaline phosphatase and GGT may indicate pathology of the biliary tract, cholelithiasis, or impaired bile outflow. This enzyme is located in the epithelium of the bile ducts, so an increase in its activity indicates cholestasis of any origin (intra- and extrahepatic). An isolated increase in alkaline phosphatase levels is an unfavorable prognostic sign and may indicate the development of hepatocellular carcinoma.

Glucose is used in the diagnosis of diabetes mellitus, endocrine diseases, and pancreatic diseases.

Ferritin indicates iron reserves in the body. An increase in ferritin in chronic hepatitis may indicate liver pathology. An increase in ferritin levels may be a factor that reduces the effectiveness of antiviral therapy.

Albumin is the main blood plasma protein synthesized in the liver. A decrease in its level may indicate liver pathology caused by acute and chronic diseases. A decrease in the amount of albumin indicates severe liver damage with a decrease in its protein synthetic function, which occurs already at the stage of liver cirrhosis.

Total protein (Protein total) - the total concentration of proteins (albumin and globulins) found in the blood serum. A strong decrease in total protein in the analysis may indicate insufficiency of liver function.

Protein fractions are protein components contained in the blood. There are quite a large number of protein fractions, but for patients with chronic hepatitis, special attention should be paid to five main ones: albumins, alpha1-globulins, alpha2-globulins, beta-globulins and gamma globulins. A decrease in albumin may indicate liver and kidney pathology. An increase in each of the globulins may indicate various disorders in the liver.

Creatinine is the result of protein metabolism in the liver. Creatinine is excreted by the kidneys in the urine. An increase in creatinine levels in the blood may indicate a disruption in the normal functioning of the kidneys. The test is done before antiviral therapy to assess its safety.

Thymol test (TT) has recently been used less and less in the diagnosis of chronic hepatitis. An increase in the TP value indicates dysproteinemia, characteristic of chronic liver damage, and the severity of mesenchymal-inflammatory changes in the organ.

Our body can perhaps be considered the most “advanced technology” that Mother Nature has created. In it, each organ is unique in its “design”, and with its capabilities it is not so surprising as it is amazing. And if you delve into the study of the whole organism, you can come across a considerable number of complex terms. Often in the tests you take, you can find such an unpronounceable phrase as increased aspartate aminotransferase. Meanwhile, this relates to the topic of amino acid breakdown. It’s worth getting to know this term a little closer.

What is the term?

This word means a special enzyme that is involved in the breakdown of almost any amino acid in our body. It is abbreviated as AST or denoted by capital letters AST. The enzyme is found in the tissues of many organs, such as:

• liver;
• heart;
• nerve tissue;
• kidneys;
• muscles;
• pancreas;
• spleen;
• lungs;
• brain tissue.

Moreover, most of the enzyme is found in the tissues of the heart, kidneys, nerve cells, and liver.

Thus, diagnosing any disease associated with these organs implies the fact that aspartate aminotransferase is elevated. In the lungs, spleen and pancreas, the amount of enzyme is not so large. At the same time, the male body differs from the female body in its high AST activity.

Functional purpose of ASAT

An enzyme is a protein molecule that is produced by the cellular tissues of internal organs. Its structure was established by Russian scientists back in the 70s. The function of the enzyme is to accelerate biochemical reactions occurring in cells. With the participation of vitamin B6, the exchange of amino acids becomes possible. During the complex transformation of many amino acids, including aspartic acid, a new compound is formed. It is thanks to it that the synthesis of glucose, which is so necessary for our body, is carried out.

Features of AST

Each of us sooner or later came across such a phrase as increased aspartate aminotransferase. Not everyone knows what this means. In this regard, let us lift the veil. In a healthy body, the enzyme is contained in the cells of the mentioned internal organs, which is the norm. Only a small portion of AST can enter the blood. For your information, the concentration of the enzyme in the heart exceeds its amount in the bloodstream by 10 thousand times.

But if the tissue of any organ is damaged, then aspartate aminotransferase, released, enters the blood and the amount of the enzyme begins to increase. The rate of growth depends on the degree of tissue damage. For example, if a myocardial infarction is diagnosed, the AST concentration will reach its maximum within 24 hours.

In some cases, the enzyme level can exceed the norm by 5 times, and this level can last for 7 days. And here someone may wonder: if aspartate aminotransferase (AST) is elevated, what does this mean? Such high activity is a characteristic sign of the patient’s serious condition, which often ends in an unfavorable outcome.

If the increase in enzyme concentration occurs at a gradual and increasing pace, this means that the infarction area is increasing. Aspartate aminotransferase activity can be triggered by the death of liver tissue.

What can be the risk of high AST activity?

Often, a high concentration of aspartate aminotransferase in the bloodstream is caused by myocardial infarction. In this case, the amount of enzyme can be 10 times more than normal, and the higher it is, the larger the area of ​​damage to the heart muscle. On the fourth day of treatment, a repeat test is usually prescribed. Its result will show whether aspartate aminotransferase is elevated or not. In the case of effective therapy, its concentration should decrease.

High levels of AST can also be observed with liver damage due to the influence of certain factors:

• Oncological diseases.
• Alcohol poisoning.
• Obesity.
• Presence of hepatitis.

Only in this case, in order to make an accurate diagnosis, it is necessary to conduct an additional examination. But elevated levels of the enzyme can also occur in completely healthy people. So, the activity can be:

• In children with inflammation.
• In women during the first trimester of pregnancy.
• With excessive consumption of alcoholic beverages.
• When taking certain medications: valerian, various antibiotics or paracetamol.

Heavy physical activity also has a negative effect in this regard. In addition, if aspartate aminotransferase is elevated, the reasons may be hidden in the use of drugs based on barbituric acid; taking contraceptives can also lead to an increase in AST.

Reasons for increased AST

The reasons for the increased level of the enzyme, as mentioned above, can be myocardial infarction. With this diagnosis, high aspartate aminotransferase activity is recorded in 95-98% of all patients. In this case, the value can reach 3000 units/l. In other cases, high levels of the enzyme are observed with liver necrosis. This disease, in turn, can be caused by hepatitis of various forms. The AST level exceeds normal values ​​by 10-100 times.

Among other diseases, it is worth noting angina pectoris, acute pancreatitis, obstruction of the bile ducts, cancer cells or liver metastases. The concentration of the enzyme can also increase due to injury, burns, the beginning of the process of muscle cell death, or under the influence of heat stroke. This can also include the patient’s condition in the postoperative period.

The fact that aspartate aminotransferase is elevated in a child may indicate the presence of hepatitis, muscular dystrophy, acute myocarditis, and jaundice.

Reasons for decreased AST

The enzyme level can not only increase, but also decrease. This happens for various reasons. This usually occurs in pregnant women. In other cases, in children and adults, due to muscular dystrophy, injuries of varying severity, cerebral infarction, hypothyroidism or acute pancreatitis, decreased levels of aspartate aminotraferase are observed. Due to a lack of vitamin B6 or a rupture of the liver, a deficiency of the protein molecule is also diagnosed.

Indications for the purpose of analysis

An analysis to determine the level of the AST enzyme must be carried out in order to identify the presence of some serious pathologies:

• whether oncological processes occur in liver cells;
• are there metastases;
• elevated blood aspartate aminotransferase may indicate the presence of infectious mononucleosis or viral damage to the lymphatic system;
• autoimmune diseases (for example, Duchenne-Becker muscular dystrophy);
• myocardial infarction;
• cirrhosis;
• the analysis will also show the presence of hepatitis of any form, including liver necrosis.

In addition, the identified abnormalities in the muscles and liver should, at a minimum, make you think about getting tested.

Only the result obtained can confirm or refute the diagnosis. This will allow you to take the necessary measures in a timely manner. If no major changes have occurred, then this is only for the better.

Preparation is important

As with some examinations, the test must be taken seriously, since taking medications, be it a medication prescribed by a doctor or a herbal decoction, can negatively affect the test results, which will be inaccurate.

Therefore, in order to know for sure whether aspartate aminotransferase is elevated or not, it is necessary to stop taking the medication. If for some reason this cannot be done, you should notify the attending physician, who must be provided with all the information regarding the drug. Namely, the dosage and time of taking it. For women, laboratory tests can ruin their pregnancy.

Carrying out analysis and norm indicators

The material for the study is exclusively venous blood or serum. It is taken on an empty stomach in the morning. The whole procedure does not take much time and is painless. The result will be ready after 6-10 hours. The serum can be stored for 48 hours at a temperature of 15-25 degrees. In cooler conditions (2-8°C) it will keep for about 6 days.

As for the question of where you can take such an analysis, you should contact specialized laboratories that conduct biochemical tests. In some cases, to find out whether AST (aspartate aminotransferase) is elevated or normal, you can undergo a test at the clinic at your place of registration or any government medical institution. You just need to first find out whether her laboratory has the necessary equipment and tools for such an analysis.

Normal indicators are different for each group of people. For example, in newborns the AST concentration is 25-75 U/l, while in slightly older children (1-18 years old) it is 15-60 U/l. Normal values ​​for women range from 10 to 36 U/l, and for men – from 14 to 20 U/l.

When alanine aminotransferase is increased or decreased, what are the methods of correction?

Alanine aminotransferase is an enzyme from the group of transferases that takes part in the metabolism of amino acids. It is found in large quantities in the cells of the heart, kidneys and liver, as well as in skeletal muscles. This enzyme is absent or found in very small quantities in the blood. It is the main indicator of cytolysis, so determining its amount in the blood makes it possible to judge the damage to the corresponding internal organs.

Alanine aminotransferase: normal

The level of this compound in blood serum depends on age and gender. Thus, for women, the ALT concentration should be no more than 31 units/l, for men - no more than 41. In children, in the first 5 days of life, the level of alanine aminotransferase reaches 49 units/l, and by the 6th month of life it increases to 56. In children 3- At 6 years, ALT is no more than 29.

Alanine aminotransferase is increased: reasons

An increase in the amount of this enzyme in the blood indicates the following pathologies:

Viral hepatitis;

Oncological process in the liver or the effect of toxic compounds on this organ, including alcohol;

Alanine aminotransferase is increased during drug intoxication;

Heart failure, other heart damage (for example, myocarditis or heart attack);

Shock that develops against the background of severe injuries or massive burns;

Necrotic process in skeletal muscles.

Other etiological factors

Typically, alanine aminotransferase is elevated in acute pancreatitis, lymphoblastic leukemia, hepatic steatosis, or infectious mononucleosis. Quite often, the level of this hormone increases in the second trimester of pregnancy. With mechanical or obstructive jaundice, its concentration in the blood also increases. It is worth noting that a blood test for ALT is carried out with a simultaneous determination of AST levels. The ratio of these two indicators makes it possible to more clearly determine the localization of the pathological process and its severity.

Alanine aminotransferase is reduced: reasons

The amount of ALT decreases with infections in the genitourinary system, oncopathologies of various etiologies, diseases of the pancreas, and with a lack of pyridoxal phosphate, which can occur with poor nutrition or frequent consumption of alcoholic beverages. In addition, low ALT levels are associated with severe liver diseases, when a large number of hepatocytes that synthesize this hormone are destroyed.

Correction of ALT levels

If alanine aminotransferase is elevated, treatment must include eliminating the etiological factor that caused this disorder. Thus, the underlying pathology is treated; choleretic drugs, hepatoprotectors, and also drugs that improve digestion are additionally prescribed. If the increase in ALT is due to the use of certain medications, then consider the possibility of using their analogues, which do not affect the level of this enzyme. It should be noted that the level of alanine aminotransferase is an important biochemical indicator, since it indicates severe diseases of internal organs, which, with timely treatment, can have a favorable prognosis.

Aspartate aminotransferase

Aspartate aminotransferase Identifiers CF code CAS number Enzyme databases IntEnz BRENDA ExPASy MetaCyc KEGG PRIAM PDB structures Gene Ontology Search PMC PubMed NCBI CAS

Aspartate aminotransferase (AST, AsAt; Also glutamate oxaloacetate transaminase) is an endogenous enzyme from the group of transferases, a subgroup of aminotransferases (transaminases).

History of the study

Aspartate aminotransferase became the first protein whose amino acid sequence (i.e., primary structure) was established by Soviet/Russian scientists. This was done in joint work by two laboratories: the Institute of Molecular Biology of the USSR Academy of Sciences under the leadership of A. E. Braunstein and the M. M. Shemyakin Institute of Bioorganic Chemistry of the USSR Academy of Sciences under the leadership of Yu. A. Ovchinnikov, the results of which were published in 1972. They studied aspartate aminotransferase from the cytosol of the pig heart, which consists of two identical subunits of 412 amino acid residues each. For revealing the structure of this protein, a team of scientists was awarded the Lenin Komsomol Prize in the field of science and technology for 1975.

Catalyzed reaction

The enzyme catalyzes the conversion of oxaloacetate to aspartate by transferring NH 3 to the first molecule. The second product of the reaction is α-ketoglutarate. The reaction plays an important role in the release of NH 3 from amino acids, which is then processed in the urea cycle, since the aspartate produced in the reaction is needed to form argininosuccinate (2nd reaction of the cycle). In addition, the reverse reaction allows the conversion of aspartate to oxaloacetate. Thus, the metabolism of aspartate (as well as other amino acids, which become oxaloacetate during their catabolism) supplies the body with the substance necessary for the process of gluconeogenesis.

Genes

In humans, there are two genes encoding different AST isoenzymes:

• GOT1 - enzyme active in the cytosol of cells
• GOT2 - enzyme active in mitochondria

Implications for medicine

Reaction catalyzed by aspartate aminotransferase

Structure of aspartate transaminase from chicken heart mitochondria

Mechanism of aspartate aminotransferase reaction

Aspartate aminotransferase is widely used in medical practice for laboratory diagnosis of myocardial (heart muscle) and liver damage.

Aspartate aminotransferase is synthesized intracellularly, and normally only a small part of this enzyme enters the blood. When the myocardium is damaged (for example, during myocardial infarction), liver (with hepatitis, cholangitis, primary or metastatic liver cancer) as a result of cytolysis (cell destruction), this enzyme enters the blood, which is detected by laboratory methods. In liver cirrhosis with cytolytic syndrome, AST levels are often elevated, but in late stages of cirrhosis (Child-Pugh class C), transaminase levels are rarely elevated.

An increase in AST that exceeds an increase in ALT is characteristic of damage to the heart muscle; if the ALT level is higher than AST, then this usually indicates the destruction of liver cells.

Normal values ​​for humans (U/l)

• Normally, AST is 0-31 U/L in women and 0-41 U/L in men.

• The normal AST content in the blood of a turtle is 50-130 units/l.