Liver function is a very important clinical indicator, but there are often problems in clinical evaluation, for example, some patients with elevated “transaminase levels” are simply considered to have “abnormal liver function”. In fact, the indicators of liver function should include the synthesis, excretion, metabolism of drugs, immunity and other functions of the liver, not just the level of transaminases.
Basic liver functions
Synthetic functions: Alb, PT, lipids and lipoproteins
Excretory functions: bilirubin, bile acids, pigments (sodium sulfobromophthalein, indocyanine green) excretion
Metabolic functions: aminopyrine, finasteride, tryptophan, urea, etc. metabolism
Immune function: gamma-globulin
Liver marker tests
Hepatocellular injury – enzymatic changes: ALT, AST, LDH, adenosine deaminate
Cholestasis: bilirubin, bile acids, cholesterol, ALP, GGT
Cirrhosis: type III, VI, I, IV collagen, hyaluronic acid, proline hydroxylase
Hepatocellular carcinoma: AFP, GGT-II, AFU, AKP-Ⅰ, aldolase A, decarboxylated thrombin
Autoimmune hepatitis: smooth muscle antibodies
Primary biliary cirrhosis: mitochondrial antibodies, IgM
The specific description of each index is as follows.
I. Liver synthetic function
(I) Albumin (Alb)
The liver is the only place to synthesize albumin, and the serum albumin level is one of the good indicators to reflect chronic liver injury. Decreased serum albumin level is seen in: insufficient nutritional intake, impaired synthesis, excessive consumption and increased loss. The serum albumin level in patients with chronic liver disease can reflect the ability of the liver to synthesize albumin and changes in the volumetric distribution of albumin, and if the serum albumin level is reduced and not easily recovered, the prognosis is often poor.
(ii) Prothrombin time
In hepatic impairment, the associated impaired synthesis of coagulation factors can lead to prolonged PT, which is one of the early predictors of abnormal liver function. prolonged PT and uncorrectable vitamin K predicts extremely poor liver function. In fulminant liver failure, PT is an important early diagnostic indicator.
(iii) Lipids and lipoproteins
Lipids and lipoproteins are not sensitive indicators of liver damage, but serum cholesterol ester levels decrease in response to hepatocellular damage and are proportional to the degree of liver damage. In chronic liver disease, lipoproteins are reduced and their levels are negatively correlated with transaminases and bilirubin.
Liver excretion function
Bilirubin
Bilirubin is one of the important indicators of liver function, the level of normal total bilirubin TBIL is 4 times normal: cholestasis syndrome
2, ALP> normal 2.5 times, ALT, AST normal 2.5 times, ALT, AST> normal 8 times: 90% for viral hepatitis
(C) Glutamyl transpeptidase GGT
90% of patients with hepatobiliary disease have elevated GGT, GGT>10 times normal, mostly from on alcoholic liver, intrahepatic and extrahepatic biliary sludge, primary liver cancer
Third, the evaluation of liver enzymatic indicators
1. A survey of a large sample of healthy people in the UK found that 6% of the asymptomatic normal population had elevated ALT and AST, and 5% of the normal population had all test results outside the “normal value” range. Therefore, some abnormal liver test results are not really abnormal.
2.The treatment of elevated single aminotransferase level is: check once, if the elevation exceeds 2 times of normal, further examination is needed.
Four, the interpretation of hepatitis B two pairs of half
Hepatitis B major triple positive HBsAg (+) HBeAg (+) HBcAb (+)
Hepatitis B minor triple-positive HBsAg (+) HBeAb (+) HBcAb (+)
Single HBsAg (+) is a hepatitis B carrier
V. Key.
1, elevated single unconjugated bilirubin is likely to be Gilbert syndrome.
2, persistent elevated transaminase levels, negative viral indicators, no alcohol consumption, probably fatty liver or non-alcoholic fatty liver hepatitis.
3, In acute fulminant liver failure, PT is an important early diagnostic indicator.
4. In patients with abnormal transaminases and jaundice, the possibility of pharmacologic liver disease should not be overlooked. In patients receiving drug therapy, weekly follow-up is required when the ALT level is less than 3 times the normal upper line, and it is better to discontinue the drug when it is greater than 3 times.
5.When the liver function index is abnormal, do not blindly take medication to correct it, you should go to a specialist hospital for consultation. Because there are certain indications for drugs for liver disease, and the price of drugs is high, and there are individual differences in specificity, and there is still no specific absolute effective drug.