Alanine aminotransferase, or ALT, and aspartate aminotransferase, or AST, are enzymes that are found in the cells of the body and that participate in amino acid metabolism. They are located only in the cells of the tissues of organs, and enter the blood only when the cell breaks up with traumatic injuries or pathologies.
Types of diseases
Excessive content of ALT indicates the development of pathology of the organ, in the cells of which there is its largest number. The causes of an increase in alanine aminotransferase are liver pathologies. Discomfort and pain in the right hypochondrium, diarrhea, icteric staining of the skin and mucous membranes, flatulence, burping with bitter are signs of an increase in ALT. When conducting a blood test, an increased level of bilirubin is added to increased ALT and AST when hepatitis develops. More often, an increase in ALT indicates other diseases. The concentration of ALT is directly dependent on the severity of the pathology.
A necrotic process in the heart muscle causes the release of these enzymes into the blood. Their increased serum content also indicates the development of other cardiopathologies: insufficiency, inflammation of the heart muscle. Additionally, the causes of increased serum ALT concentration may be injuries in the body, which are associated with damage to muscle tissue, and pancreatitis.
A biochemical blood test for ALT and AST can talk about the pathology of the liver, pancreas, heart. With cardioinfarction, the concentration of AST increases several times, and ALT - a little.
Indications for
The organs of the human body contain a different amount of ALT and AST enzymes, therefore, an increase in the concentration of a particular enzyme indicates damage to a specific organ:
• ALT is primarily found in liver, cardiac, renal, and pancreatic cells. In the event of the destruction of these organs, a lot of ALT is released into the blood. Then, to confirm the diagnosis, it is necessary to study specifically on alanine aminotransferase.
• AST is mainly found in nerve, muscle, liver, and heart cells, and in small quantities in pancreatic cells, lung, and kidney tissue. Therefore, in this case, research on aspartate aminotransferase is necessary.
A blood test of ALT and AST (transcript) indicates the condition of the organs. Their increase indicates damage to the tissues of the organs in which these enzymes are located. And, accordingly, a decrease indicates a cure. A slight increase in ALT in the first trimester of pregnancy is quite possible, but it is necessary to re-examine the blood for aminotransferases to exclude liver damage.
A biochemical blood test (indicators of ALT, AST) is prescribed when cardioinfarction is suspected, they serve as an early sign in this acute pathology. Decoding AST in biochemical analysis makes it possible to diagnose and monitor the dynamics of other changes in the heart muscle, liver diseases and diseases of striated muscles.
Preparation for blood sampling for the study
Blood for biochemical analysis is taken in the morning on an empty stomach from a vein. At the time of the analysis, 8 hours should pass. from the last food intake. In 24 hours alcohol and fried and fatty foods are prohibited before blood sampling. It is recommended to reduce physical activity.
Immediately after an ultrasound scan, X-ray, fluorography, colonoscopy or physiotherapy procedures, it is also not recommended to take blood for analysis, otherwise the decoding of biochemistry will be distorted. In 1-2 weeks. before biochemical research, you need to stop taking medication. When it is impossible to comply with this condition, in the direction of the analysis, the doctor makes a note about taking the drugs and their dose. Biochemical
analysis of blood (decoding ALT, AST) can be affected by severe physical exertion, as well as alcohol consumption and hemolysis.
Decoding of a blood test - ALT, AST: normal
How much of these enzymes should be contained in the blood of a healthy person? Conducting a biochemical blood test (decoding ALT, AST), the norm for women is in the range from 31 to 35 units per liter of blood. For the stronger sex, this figure is slightly different. The norm of ALT in the blood in men (decoding of biochemistry) is from 41 to 50 units / liter. In newborns (up to 1 month), the normal reading corresponds to 75 units, from 2 to 12 months. - not more than 60 units, and from a year to 14 years old - less than 45 units. A blood test (decoding ALT, AST) with an increased indication may indicate cirrhotic damage or acute inflammation of the liver, congestive or hemolytic jaundice, other liver pathologies (and neoplasms, including), angina pectoris in the attack stage, acute rheumatic heart disease, myopathy, bile stasis , thromboembolic disease of the pulmonary artery and acute pancreatitis.
ALT and AST blood analysis (decoding) with an increase in indications is observed for traumatic injuries, cardiac surgery or angiocardiography. An increased AST indicator of 20–50 times in some cases indicates a hepatic pathology accompanied by necrosis, and hepatitis of viral etiology. A 2-5-fold increase in AST can indicate diseases with hemolysis, muscle injuries, acute pancreatitis and gangrene. With dystrophic phenomena in the muscles and dermatomyositis, an 8-fold increase in AST is observed.
Ritis coefficient
In order to obtain accurate answers, an ALT and AST blood test (transcript) shows the ratio of transferase indices. This ratio shows the de Ritis coefficient carried out in one serum study. In the case when the number is higher than the norm (N = 1.3), this indicates the presence of a cardioinfarction, and when it is lower than the normative indicators - about viral hepatitis.
Since aminotransferases have tissue localization, the interpretation of the AST blood test shows myocardial pathology, and ALT shows liver pathology, that is, the presence of cell decay:
• When there is an excess of 2 or more times, a heart attack is determined in the heart.
• A blood test of ALT and AST (transcript) shows a significant excess - this is evidence of infectious hepatitis in the incubation period.
• With a decrease in aminotransferase, there is a lack of pyridoxine in the body. Here, differential diagnosis with pregnancy is necessary.
Tactics
Normally, serum transferases exist in small volumes. All options for increasing aminotransferase levels are necessarily investigated.
To begin with, a second biochemical blood test (decoding ALT, AST) should be performed. Repeated examination of some individuals (donors) in about a third of cases shows a normal level.
Next, you need to carefully collect the anamnesis and conduct a full examination.
The role of history in decryption
An anamnesis involves information about taking medications, a blood transfusion, the presence of jaundice or hepatitis syndrome, familial liver diseases or the presence of a cirrhotic process in it, abdominal pain, cancer, diabetes, obesity, or, conversely, rapid weight loss.
Family liver diseases are alcohol dependence, Wilson’s disease, etc.
If ALT and AST blood analysis (decoding) showed above normal values less than twice, it is necessary to organize observation and a 2-fold examination. This tactic is optimal for patients.
Blood test ALT and AST - transcript for some diseases
A slight increase in transferases is indicative of non-alcoholic fatty liver damage, including "fatty liver", non-alcoholic steatohepatosis, and chronic viral hepatitis.
A moderate increase can exist with viral or alcoholic inflammation of the liver and various chronic liver diseases with or without cirrhotic damage.
An elevated level is typical for severe acute hepatitis, toxic or drug necrosis, shock or hepatic ischemia.
An excessively high level (more than 2000-3000 U / L) exists with an overdose of acetaminophen and when using the drug in alcohol-dependent patients, with shock or / and hepatic ischemia.
It should be noted, since ALT is in red blood cells, it is necessary to prevent their decay when preparing serum for analysis. ALT may decrease when serum is stored for several days.
The role of medicines, herbs and other substances
A thorough history and decipherment of laboratory results are important for identifying drug-induced increases in transferases. Similar liver damage is detected in 1-2% of cases of chronic inflammation of the liver. They are associated with the use of antibiotics, antiepileptic drugs, hydroxymethylglutaryl-CoA reductase inhibitors, non-steroidal anti-inflammatory drugs and medications for the treatment of tuberculosis.
The easiest method to determine the dependence of the increase in aminotransferases with some means is to cancel it and observe the level of enzymes. Without canceling the tool, this dependence cannot be determined.