Liver function refers to the ability of the liver to function effectively and healthily. Liver function examination refers to checking whether the detoxification, synthesis, metabolism and other functions of the liver are normal. Below are the methods for liver function testing.
What are the items of liver function examination?
Due to the diversity of liver function, the methods and items for examining liver function are also diverse. Serum proteins related to liver function include total serum protein, serum turbidity, agglutination test, albumin to globulin ratio, and alpha fetoprotein test. Serum enzymes associated with liver disease include alkaline phosphatase, alanine aminotransferase, lactate dehydrogenase, and aspartate aminotransferase. The detection related to biotransformation and excretion is sulforaphane. Bilirubin quantification and sodium retention tests such as urinary three gallbladder test are closely related to bilirubin metabolism.
2. Precautions for liver function examination
(1) On the day before the liver function examination, do not eat high-fat or high protein foods, and do not eat again after 9 pm. On the day of the examination, do not eat breakfast or drink water in the morning. The liver function test should involve drawing blood on an empty stomach, usually for 8-12 hours;
(2) On the morning of the liver function test, the patient cannot engage in physical exercise or strenuous activities;
(3) Try to avoid liver function tests during intravenous infusion or within 4 hours of medication. If the patient's physical condition allows, it is best to stop taking the medication 3-5 days before the liver function test.
(4) Ensure sufficient sleep and have a light diet.
(5) The day before the liver function test, the patient should not consume foods rich in carotenoids and lutein.
3. The importance of liver function testing
Regular check ups of liver function are very important. Because the liver is the largest substantive organ in the human body, responsible for various physiological functions. When different reasons cause severe damage to liver cells, it can lead to abnormal metabolism of various substances in liver cells, resulting in corresponding changes in the levels of liver related metabolites and acids in the blood. Liver function tests can help patients detect and diagnose certain diseases as early as possible, such as acute and chronic hepatitis, alcoholic liver disease, drug-induced hepatitis, fatty liver disease, cirrhosis, and liver and gallbladder diseases. At the same time, blood tests must be taken on an empty stomach.
4. Methods for liver function examination
4.1 Determination of serum total bilirubin
Total bilirubin is a lipophilic substance synthesized by the liver and converted and secreted in the liver. The concentration can reflect the liver's ability to metabolize toxic substances. The normal range is 5-21 μ mol/L.
4.2 Determination of serum indirect bilirubin
Indirect bilirubin mainly exists in the blood and is metabolized into hydrochloric acid through changes in bilirubin in liver cells. It is commonly used to diagnose diseases such as hemolytic anemia and cholestatic jaundice.
4.3 Determination of alanine aminotransferase (ALT)
ALT is a liver function indicator that represents the enzyme released into the bloodstream after cell disintegration and is directly proportional to the degree of cell damage. Normal adult ALT values should generally be within the range of 5-40U/L.
4.4 Determination of Aspartate Aminotransferase
Aspartate aminotransferase (AST) is an enzyme present in liver cells and myocardial cells. If the liver or myocardial cells are damaged, the level of AST will increase. Normal adult AST values are within the range of 5-40U/L.
4.5 Alkaline Phosphatase Measurement
Alkaline phosphatase (ALP) is an enzyme distributed in various tissues, including liver, biliary tract, bone, and liver. It is mainly used to detect biliary obstruction, liver metabolism, and bone morphology. The normal adult ALP value is between 30-120U/L.
4.6 Serum protein determination
The synthesis function of the liver includes the synthesis of plasma proteins such as albumin and globulin. By measuring the content of these proteins, the health level of liver function can be understood. The normal albumin level is 35-55g/L, and the globulin level is 20-40g/L.
In short, the above are the methods for liver function testing. Regular liver function tests can detect certain diseases as early as possible, such as acute and chronic hepatitis, alcoholic liver disease, drug-induced hepatitis, fatty liver, and cirrhosis, so people must undergo regular liver function tests.