The tryptophan tolerance test is a liver function clearance test. When the liver cells are damaged, the amount of the enzyme is reduced and the viability is decreased, and the clearance of tryptophan is slowed down, so that the total amount of tryptophan in the plasma is increased. When the function of hepatocytes decreased significantly, the synthesis and carrying capacity of albumin decreased, the amount of free tryptophan increased significantly, and the ratio of free tryptophan (F)/total tryptophan (T) increased. When hepatic coma, plasma free tryptophan is significantly increased on fasting due to competition for albumin carriers such as free fatty acids.

Basic Information

Specialist classification: Digestive examination classification: liver function test

Applicable gender: whether men and women apply fasting: fasting

Tips: When taking blood, it is necessary to avoid the effects of digestion and absorption of food. It should be taken in the early morning on an empty stomach. Normal value

F < 7.5 μmol/L, T < 85 μmol/L, F/T < 0.14.

Clinical significance

1. When mild liver function damage, F>7.5μmol/L, T>85μmol/L; moderate liver damage. F≥10μmol/L; in severe liver damage, F≥12μmol/L, F/T≥0.14.

2. T is elevated in chronic persistent hepatitis, T and F are elevated in chronic active hepatitis, and F is elevated in cirrhosis. Severe liver disease can only measure fasting tryptophan, no tolerance test.

High results may be diseases: liver damage, liver cirrhosis, chronic hepatitis precautions

(1) The plasma amino acid concentration of normal people fluctuates day and night, with a peak at 8 to 10 in the morning and a trough at midnight. When taking blood, it is necessary to avoid the effects of digestion and absorption of food. It is better to take blood on an empty stomach in the morning.

(2) If the specimen is not suitable for hemolysis, it may lead to a false increase in the measurement results.

Inspection process

Immediately after venous blood collection, the test is performed. The detection method is the same as the fluorescence operation method.

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.