Alanine aminotransferase (ALT), also known as alanine aminotransferase (GPT), is mainly found in various tissue cells and is most abundant in hepatocytes. In the acute phase of various hepatitis, drug-induced hepatocellular necrosis and other diseases, hepatocyte enzymes are released into the blood in a large amount, so that serum ALT activity is significantly increased, so it is an important indicator for the diagnosis of viral hepatitis, toxic hepatitis and other liver diseases. .

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:
Adult: 5-40U/L

Above normal:
Found in the active period of viral hepatitis.



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

The enzyme was measured at a temperature of 37 ° C, and the substrate solution contained no P-5 '-P component. Adult ALT is 5 ~ 40U / L.

Clinical significance

1. Viral hepatitis occult infection: Serum ALT assay is a common indicator for screening asymptomatic patients with occult viral hepatitis infection in non-selective populations, with certain sensitivity and specificity. Especially in the choice of blood donors, an increase in serum ALT equivalent to 1.5 times the upper limit of the reference value can be used as a basis for eliminating blood donors who may be infected with hepatitis C (HCV).

2, acute viral hepatitis: typical cases of acute viral hepatitis in the first 1 to 2 weeks before the onset of jaundice, serum ALT, AST activity began to rise rapidly, reached a peak after the appearance of jaundice, and maintained for 1 to 2 weeks, then quickly declined It will return to normal after 6 to 7 weeks after the appearance of Astragalus. In the acute phase, the elevation of serum ALT and AST is basically parallel, and the increase of ALT is generally greater than AST. The evolution of serum ALT in different types of acute viral hepatitis varies. In acute hepatitis, the increase of serum ALT and AST can roughly reflect the degree of hepatocyte necrosis, that is, the increase of ALT is generally parallel with the degree of hepatocyte damage. For example, the severity of serum ALT in patients with severe jaundice is generally higher than that without jaundice. Hepatitis is large. However, the relationship between the two is not entirely the same. In fulminant hepatitis, ALT has been released due to extensive and severe necrosis of hepatocytes, and the ALT half-life is shorter, resulting in a gradual decrease in blood enzyme activity, while serum bilirubin (TBil) continues to rise. High, the two no longer maintain a parallel relationship, the phenomenon of so-called "enzyme separation" occurs.

3, chronic active hepatitis (slow live liver): patients with serum ALT also continue or irregularly increased, the increase (mostly 3 to 5 times higher than normal) is generally greater than chronic persistent hepatitis (slow liver, CPH) ( Most are 1 to 2 times higher than normal).

4. Serum ALT is a good indicator of the activity of chronic hepatitis B. Elevated serum ALT is associated with HBV replication in vivo.

5, serum m-ALT detection has a certain diagnostic value for judging the degree of acute hepatitis liver parenchymal damage and the differential diagnosis of slow-lived liver and slow-moving liver.

6, serum ALT can be used as an indicator of the efficacy of interferon on chronic hepatitis C (CH-C).

High results may be diseases: viral hepatitis, hepatitis B virus, hepatitis C virus, chronic hepatitis, liver damage considerations

1, severe hepatitis due to a large number of hepatocyte necrosis, at this time the blood ALT can only be slightly increased, often decreased significantly at the end of the dying, but the bilirubin is progressively elevated, the so-called "enzyme bile separation", often a sign of liver necrosis .

2. The serum of ALT in a few people continued to increase for a long time, and there was no obvious pathological change in liver perforation, and the prognosis was good.

Inspection process

Immediately after venous blood collection, the test is performed.

(1) Single-reagent method: The specific operating procedures are based on the model of the automatic or semi-automatic biochemical analyzer owned by each hospital and the operating instructions. The following is an example of a semi-automatic biochemical analyzer. 1 serum dilution: 100 μl serum, plus 1000 μl ALT substrate solution, the serum dilution factor is 11, serum accounted for 0.0909. 2 main parameters: coefficient 1768 incubation time 90s continuous monitoring time 60s cuvette light path 1.00cm wavelength 340nm sample volume 500μl temperature 37 °C.

(2) Two-reagent method: Take a semi-automatic biochemical analyzer as an example. 100 μl of serum, 1000 μl of reagent (I), mixed, and incubated at 37 ° C for 5 min. Then, 100 μl of the reagent (II) was added and mixed. The ALT catalytic reaction is initiated. At a wavelength of 340 nm, the cuvette has an optical path of 1.0 cm and a lag period of 30 s, and the rate of decrease in absorbance is continuously monitored for about 60 s. The ALT activity unit was calculated based on the rate of decrease in absorbance during the linear reaction period (-?A/min).

Not suitable for the crowd

Generally no 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.