Aspartate aminotransferase (AST) is commonly referred to as aspartate aminotransferase (GOT), which has a higher myocardial content, followed by liver, and an intrahepatic AST/ALT ratio of 2.5:1.0. Serum AST assay is mainly used for the diagnosis and therapeutic observation of myocardial and hepatobiliary diseases and bone marrow diseases. Common methods for determining AST are colorimetry and continuous monitoring.

Basic Information

Specialist classification: Digestive examination classification: liver function test

Applicable gender: whether men and women apply fasting: fasting

Analysis results:

Below normal:
No clinical significance.

Normal value:
Serum aspartate aminotransferase: 5-40U/L

Above normal:
Many drugs in clinical treatment can increase serum aspartate aminotransferase. In myocardial infarction, serum aspartate aminoase starts to increase in 6-12 h, peaks in 24-48 h, and returns to normal after 3-6 days.

negative:

Positive:

Tips: Before the examination, the diet is light and alcohol is prohibited. Check for an empty stomach in the morning. Normal value

(1) Colorimetric method 8 to 28 Carmen units.

(2) Continuous monitoring method does not contain P-5'-P in the matrix, and adults 5 to 40 U/L.

Clinical significance

Because AST molecular weight is smaller than ALT, it is higher in the liver than ALT, but the half-life is shorter. Therefore, at different stages of liver damage, the magnitude of the increase and their ratio are also different.

According to its activity and ratio change, it can be used for the identification of liver diseases and the judgment of liver cell damage. The serum AST/ALT ratio of healthy people is 1.15:1.

(1) AST increased in acute hepatitis, but the increase was not as good as ALT, and the AST/ALT ratio was <1. If the ratio is significantly elevated, it indicates a fulminant hepatitis.

(2) Chronic hepatitis, especially in cirrhosis, the increase in AST is greater than ALT, so the ratio determination is helpful for the differential diagnosis of liver disease. In chronic hepatitis, the ratio is increased in the order of chronic persistent hepatitis, chronic active hepatitis, cirrhosis, and liver cancer (this ratio > 2). In the recovery period of hepatitis, if ALT has returned to normal, and AST is still slightly elevated, it indicates that it has not recovered.

(3) AST activity increased significantly in acute myocardial infarction, and began to increase at 4 to 12 hours after onset, peaking at 20 to 48 hours. Therefore, AST measurement is one of the important enzymological indicators for the diagnosis of acute myocardial infarction. AST is normal when angina pectoris, so it can be used for differential diagnosis.

(4) Other muscle diseases, such as progressive muscular dystrophy, dermatomyositis, polymyositis, etc., also increased AST, and its AST/ALT ratio was greater than 1.

High results may be diseases: hepatitis, liver fever, pediatric myocarditis, congenital hepatic cysts

(1) Many drugs in clinical treatment can increase serum aspartate aminotransferase, such as rifampicin, tetracycline, gentamicin, erythromycin, kanamycin, chloramphenicol, griseofulvin, Cyclosporine, phenacetin, phenobarbital, diethylstilbestrol, oral contraceptives, diazepam, quinidine, phenylbutazone, sulfonamides, furans, etc., especially long-term use of these drugs on the liver The cells are damaged and have different effects on the determination of aspartate aminotransferase activity.

(2) In myocardial infarction, serum aspartate aminoase began to increase from 6 to 12 h, peaked at 24 to 48 h, and returned to normal after 3 to 6 days.

Inspection process

Immediately after venous blood collection, the test is performed.

(1) Colorimetric method: With the ALT colorimetric assay, only the enzymatic reaction time was changed to 60 min, and the AST standard curve was checked.

(2) Continuous monitoring method: The analysis conditions should be determined according to the specifications of the instrument of this laboratory. Main parameters: same as ALT continuous monitoring method.

Not suitable for the crowd

Generally there are no special taboos.

Adverse reactions and risks

1. Infection: Pay attention to aseptic operation when collecting blood, avoid contamination of water and other parts at the blood collection site to avoid local infection.

2, bleeding: after the blood is given a full compression time, especially coagulopathy, bleeding tendency, to avoid local subcutaneous oozing, bruising and swelling.