The liver is one of the most important organs of man. It is with its help that toxins and drug residues are broken down and eliminated. Every day, it is subjected to tremendous stress, but, nevertheless, is quickly restored. Unfortunately, this only happens until a certain point. To determine the functional capabilities of the liver, liver tests help. Decryption of the analysis will help to identify the problems of this body.
Hepatic tests - what is it
In order to determine what condition the liver and bile ducts are in, modern medicine uses a number of laboratory tests, collectively called hepatic tests. Material for the study is obtained by taking venous blood, and with its help do the following tests:
- AST, ALT;
- bilirubin;
- alkaline phosphatase;
- total protein;
- thymol test;
- albumen.
These laboratory tests allow you to evaluate existing disorders, as well as the ability of the liver to support one of its most important functions - the synthesis of enzymes and other substances necessary for normal life.
Hepatic tests - ALT, AST
Endogenous enzymes AST and ALT are an important component in the production of certain amino acids. The norm of AST and ALT differs depending on the gender and age of the patient, as well as on his body weight, temperature and lifestyle. In a healthy body, their number is negligible, and in men a little more than in women.
Aspartate aminotransferase (AST)
This enzyme is found, as a rule, in the tissues of the liver and partially in the heart and muscles. The norm for women is 10-35 U / L, and for men - from 14 to 20 U / L. An increase in normal indicators may indicate damage to those organs where it is contained. Depending on how much the norm is exceeded (and this indicator can vary from several units to an increase of five to ten times), the degree of damage is determined. In order to make sure that the pathological process affects the liver, complete liver function tests are performed. Decryption of the analysis confirms or refutes suspicions with a high degree of probability.
Alanine aminotransferase (ALT)
The liver enzyme, like AST, is involved in the metabolism and in particular amino acids. Like AST, it is predominantly present in liver cells, in muscle and cardiac tissues. Its content in women normally varies from 10 to 30 units / liter. In men, the norm is 10-40 units / liter. Its excess also signals damage to tissues that contain alanine aminotransferase. If the norm of AST and ALT is increased, then this may indicate the presence of diseases such as viral hepatitis, acute alcohol or food poisoning, cirrhosis, and the presence of parasites.
Bilirubin
There are three types of bilirubin - direct (connected), indirect (unbound) and common, while the latter does not exist by itself, but is a combination of the first and second type. This pigment substance is formed due to the breakdown of heme, which, in turn, is part of hemoglobin. The process takes place in the liver cells. In the presence of any pathological process in hepatocytes or bile ducts, a change in the level of bilirubin in the blood serum occurs.
The total bilirubin can range from 3.3 μmol / L to 20.5, while the direct is about 25% of the total, that is, up to 3.3 μmol / L, and indirect - 75% (13.6-17 , 1 μmol / L). In the event that the liver tests are elevated, various inflammatory processes in the liver and gall bladder can be suspected. Visually, an increase in bilirubin level is manifested by jaundice.
Alkaline phosphatase
Another enzyme of the bile duct, necessary for the normal functioning of the body, is alkaline phosphatase. It plays an important role in phosphorus-calcium metabolism, directly affecting the state of bone tissue. However, in large quantities, alkaline phosphatase is also present in the tissues of the liver, as well as in the intestinal mucosa and mammary glands. Its normal indications depend on the age of the patient. In the age group up to 30 years, the normal values of alkaline phosphatase are 32–92 IU / L, and older - from 39 to 117 IU / L. What will a blood test give? Hepatic tests, as a rule, do not show a decrease in this indicator, and its increase indicates metabolic disorders, in particular - a violation of phosphorus transport. This can be a violation of the outflow of bile in the bile ducts (cholestasis), cirrhosis, parasitic diseases, acute alcohol poisoning.
Thymol test
The thymol test is another test included in the liver test. The interpretation of the analysis in this case shows the ability of the liver to synthesize protein components of the blood. Thymol test belongs to sedimentary. To carry it out, a saturated solution of thymol is added to the mixture of blood serum and buffer solution , and after half an hour the severity of the turbidity of the solution is evaluated. Normal values for this sample range from 0 to 5 units. The increase occurs with impaired protein synthesis and can signal viral hepatitis, cirrhosis and some connective tissue diseases. How useful is such a blood test? Hepatic tests, and thymol in particular, allow already in the early stages, without waiting for clinical manifestations, to determine the disease and begin adequate therapy.
Albumen
One of the main plasma proteins is albumin. It is a leading component in maintaining oncotic blood pressure and, as a result, affects the volume of circulating blood. In addition, albumin plays an important role in transport function, binding to bile acids, bilirubin, calcium ions and medicinal substances. Normally, albumin is in the range of 35 - 50 g / l. An increase in indicators is observed with severe dehydration, a decrease is an occasion to suspect inflammatory processes in the liver, sepsis, rheumatic processes. In addition, a decrease in serum albumin is possible with prolonged starvation, the use of oral contraceptives, steroids, and smoking.
Total protein
By the term “total protein” it is customary to mean the total concentration of globulins and albumin in the blood serum. This is the main component of protein metabolism in the human body. It performs many functions: it maintains a constant blood PH, participates in coagulation processes, immune reactions, and the transfer of fats, hormones and bilirubin to organs and tissues. Why does the doctor suggest patients to take a liver test? Decryption (the norm of this indicator should be from 64 to 86 g / l) will help a specialist to understand if these functions are violated. So, an increase in protein can be observed in acute and chronic inflammatory processes and infectious diseases, as well as with extensive burns. A decrease in indicators can be the result of bleeding, kidney disease, which are accompanied by significant loss of protein (glomerulonephritis), oncological processes.
Hepatic tests, the decoding of the analysis of which is of great importance in the diagnosis of many pathological conditions of the liver and other organs, are given in the morning, on an empty stomach (the last meal should be done at least 8 hours before the test). On the eve, it is necessary to exclude alcohol and fatty foods.