How Do I Interpret My Liver Function Test Results?

Liver function tests refer to tests that reflect liver synthesis, metabolism, transport, immunoregulatory functions, and liver cell damage, and are often used for the diagnosis and efficacy observation of liver diseases.

Basic Information

Chinese name

Liver function test

Operation method

Serum protein assay, serum enzyme assay, etc.

Clinical significance

Commonly used in the diagnosis and efficacy observation of liver diseases

Preparation for liver function test

Explain the purpose, method, etc. of the operation to the person being tested to eliminate concerns. The venous blood was selected for testing, and a light diet was taken 1 day before blood collection, avoiding alcohol to avoid affecting the results, avoiding emotional tension during blood collection, and fasting on the day of blood collection.

Liver function test operation method

1. Determination of serum proteins Different types of proteins are often measured using different methods. Albumin, globulin, and other commonly used chemical methods and electrophoresis methods to measure, fibrinogen is often used to determine the thermal precipitation turbidimetry method, alpha-fetoprotein is often measured by enzyme-linked immunosorbent assay or radioimmunoassay.
2. Serum enzyme measurement: Transaminase, alkaline phosphatase, -glutamyl transferase, monoamine oxidase, etc. are usually detected in serum. Generally, Lai's colorimetric method and rate method are used for detection. At present, the rate method commonly used in clinical practice is mostly measured by a semi-automatic analyzer. Take serum and the corresponding substrate buffer, and immediately inhale the automatic analyzer, incubate at 37 ° C, compare the color at a specific wavelength, perform absorbance measurement, and calculate the corresponding enzyme. Of activity.
3. Serum bilirubin is usually determined by diazo reagent method or bilirubin oxidase method. Serum and corresponding reagents are added to the test tube according to the type of substance to be measured, and the color is compared at a specific wavelength after mixing. , Read the absorbance of each tube, compare and determine the corresponding bilirubin concentration.
4. Serum bile acid determination commonly used methods include high performance liquid chromatography, radioimmunoassay, enzyme immunoassay, and bile acid colorimetry. Among them, the bile acid colorimetric method is simple, fast, and can be manually operated. Automated analysis is a commonly used method for the determination of serum bile acids in clinical laboratories. The specific operation is as follows: adding serum and a special reagent containing enzymes in a test tube, mixing them at a specific wavelength for colorimetry, reading the absorbance of each tube, and calculating bile acid concentration.
5. Blood ammonia determination methods include micro-diffusion method, ion exchange method, glutamic acid dehydrogenase method and ammonia ion-selective electrode method. Among them, the micro-diffusion method has been eliminated, and the most widely used method is glutamic acid dehydrogenase method. The test tube is added with serum, a-ketoglutarate and reduced coenzyme , and finally glutamate dehydrogenase is added. The rate of decrease of blood ammonia is proportional to the concentration of blood ammonia. The absorbance is measured at a specific wavelength, and the same treatment standard Tube comparison to calculate blood ammonia content.
6. Determination of coagulation factors (1) Prothrombin time (PT): The test plasma is added with an excess of calcium-containing tissue thromboplastin, and the recalcified plasma activates factor X to Xa through an exogenous activation pathway in the presence of tissue factors, Xa converts prothrombin to thrombin. Thrombin converts fibrinogen to fibrin and coagulates. The time required for coagulation is the prothrombin time.
(2) Activated partial thromboplastin time (APTT): Thrombin is added to the plasma to be tested, and fibrin is converted to insoluble fibrin and coagulated with the participation of calcium ions. The time required to measure coagulation is the activated partial thromboplastin. Enzyme time.
(3) Thrombin time measurement (TT): The test plasma is added with an appropriate amount of thrombin, and fibrinogen is converted to insoluble fibrin and coagulated. The time required for measurement is the thrombin time.
(4) Determination of fibrinogen concentration: in the presence of high concentration of thrombin, the clotting time of the diluted plasma to be measured is inversely proportional to its fibrinogen content. The clotting time of the diluted plasma was measured, and the fibrinogen concentration was obtained by conversion.
7. Serum prealbumin is commonly measured by cellulose acetate film electrophoresis, immunodiffusion and turbidimetry.

Clinical significance of liver function test

1. Serum protein The serum protein of patients with liver disease can have a certain degree of qualitative and quantitative changes. It varies according to the nature, degree and duration of liver disease. Many other diseases such as acute and chronic infections, malignant tumors, and connective tissue diseases, Gastrointestinal diseases and malnutrition can have serum protein changes.
2. Serum enzyme (1) Transaminase: a sensitive indicator of liver cell damage, which is elevated in liver damage caused by hepatitis, cirrhosis and other diseases.
(2) Alkaline phosphatase: Normal human serum alkaline phosphatase mainly comes from the liver and bones, and its activity can be used as an auxiliary diagnostic indicator of liver, gallbladder and bone diseases.
(3) -glutamyltransferase: It is mainly used to diagnose hepatobiliary diseases, primary or metastatic liver cancer, obstructive jaundice, intrahepatic or extrahepatic biliary obstruction, viral hepatitis, serum -glutamate during cirrhosis Elevated acyltransferase.
(4) Monoamine oxidase: In cirrhosis and acute severe hepatitis, monoamine oxidase activity is significantly increased.
3. Serum bilirubin Determination of serum total bilirubin can help diagnose jaundice and the degree and type of jaundice. Direct bilirubin (combined with bilirubin) and serum total bilirubin can be measured simultaneously. The ratio of the two can be used for identification. Jaundice type.
4. Serum bile acids Any pathological process that causes liver cell damage may cause elevated bile acids in the blood. It is found in various types of liver disease, cirrhosis, fatty liver, and also acute and chronic biliary obstruction. Among them, fasting bile acid measurement is a sensitive, specific and relatively simple liver function test. It is one of the most sensitive liver function tests. It is particularly suitable for the diagnosis of patients with suspected liver disease but other biochemical test results are normal or mildly abnormal. .
5. Blood ammonia blood ammonia determination is mainly used for the detection and observation of patients with liver coma. Whether patients with severe liver dysfunction can eat high protein to supplement nutrition also needs to determine the blood ammonia content to determine, clinical blood ammonia measurement is also commonly used as a control and observation indicator for patients with severe liver dysfunction to enter the high protein diet.
6. Coagulation factor Liver is closely related to blood coagulation. Except for calcium ion and 20% factor , various coagulation factors are synthesized in the liver. The most common methods are the measurement of prothrombin time and activity. In patients with severe hepatitis, if prothrombin activity is below 40% and does not rise continuously, it is an indicator of poor prognosis.
7. Serum prealbumin is synthesized by hepatocytes, and its half-life is only 1.9 days, which is significantly shorter than serum albumin. Therefore, it has special diagnostic value for acute liver damage (such as subacute liver necrosis), especially liver damage within 1 week after onset.