ALT, AST are special proteins, or rather, enzymes contained in cells that take an active part in the metabolism of amino acids - those substances from which proteins are built. Both ALT and AST are contained exclusively in the cells of the human body. There is only one reason why ALT, AST enter the bloodstream - this is damage or destruction of the cells in which they were located. These enzymes are not contained in the same amount (equally) in all organs. Therefore, if the level of one of these enzymes in the blood has increased, this may be a sign of the appearance of the disease in one or another organ. So, for example, during the course of any liver disease, AST increases to a greater extent than AST. In acute myocardial infarction, ALT activity is also significantly higher than in AST. AST activity increases significantly with severe damage to the hepatocyte. In general, AST activity refers on average to ALT activity as 1 to 3 (the so-called de Ritis coefficient). About 10 or 15 days before the onset of jaundice symptoms, the activity of these enzymes also increases. And a few weeks before the onset of hepatitis B, an increase in ALT and AST also appears , which reaches a maximum in the second or third week of the course of the disease. And with a favorable course of this disease on the 30-40th day, the amount of ALT again returns to its norm, and the amount of AST - by 25-31. If the increase in ALT and AST is repeated, then this indicates that tissue necrosis of the diseased organ has recurred or is progressing. But if the disease has passed from an acute to a chronic period, then the amount of the above enzymes in the blood does not fall over time, remaining stable or even continuing to grow.
With the occurrence of cirrhosis of the liver in its latent form, an increase in these enzymes is practically not observed. However, if the patient has active cirrhosis, then the increase in ALT and AST is persistent, but rather small. Such an increase was found in the vast majority of those who suffer from an active form of liver cirrhosis.
To record the activity of ALT, more sensitive tests are used than those used to determine the amount of AST in the patient's blood. A blood test will help determine the activity of these enzymes. ALT is mainly found in the cells of organs such as the liver, skeleton muscles, heart, kidneys, and pancreas. If any damage to these organs has occurred (most often due to a disease), then ALT penetrates the blood, which should not be possible provided that the body is absolutely healthy. An important role in diagnosing an increase in undesirable enzyme activity is a timely blood test. ALT, AST, which got into the blood, it is almost impossible to determine in another way. An exception can only be a urine test.
AST is also found in the myocardium, skeleton muscles, liver cells and nerve tissue. Less in the kidneys, pancreas, and lungs. If the above organs are damaged, this leads to the fact that the level in the blood of AST increases and significantly exceeds the norm. So, an increase in ALT and AST is the first sign that problems have occurred with any of the organs in which these enzymes are contained.
The rate of enzymes for women and men is not the same. On average, for men ALT is not higher than 47 units per liter, and for women ALT, AST, both indicators should not exceed 31 units per liter. For children, these indicators differ by age and gender. In boys, the norm of AST, ALT on average can be several units per liter more than the same indicator for their peers.
An increase in these enzymes is not always a sign of illness. For example, an increase in ALT, AST is often found in those who are completely healthy carriers of the hepatitis B antigen. This indicates that asymptomatic but rather active processes are taking place in the liver. Quite often, mothers worry when they find out what the blood test was like - ALT, AST are elevated in the child. If the child is small and his age does not exceed 6 months - in this case, the level of these substances in his blood may be exceeded, and this is not a violation of the norm.
If, as shown by a blood test, ALT, AST in a pregnant woman is not normal, then this is most likely a consequence of biological rearrangements in the body of a woman. Approximately in the first 6 months of the pregnancy process, ALT may fall (however, in some cases, it rises during this period, which is also not a sign of the disease). Further, shortly before birth, the amount of these enzymes in a woman can exceed the norm by two to three times. This is usually eloquently testified by a blood test. ALT, AST, elevated during pregnancy, usually do not talk about any disease.