What Are the Routine Tests for Liver Function?
Liver function is a crucial indicator reflecting the health of the liver. In the event of liver-related diseases, the first step is to check liver function. Liver function tests provide valuable insights and are clinically significant. These tests can be conducted through professional methods, as the liver is an internal organ, many patients are interested in understanding the specific items included in liver function tests. Let's explore what are the routine liver function tests:
(1) Indicators reflecting liver parenchyma damage mainly include alanine aminotransferase (ALT) and aspartate aminotransferase (AST). ALT is the most commonly used and sensitive indicator. When 1% of hepatocytes become necrotic, the serum ALT level can increase by one fold. Persistent elevation of AST, with values exceeding ALT, often indicates severe liver parenchyma damage and is a sign of increasing chronicity.
(2) Indicators reflecting bilirubin metabolism and bile stasis mainly include total bilirubin (TBil), direct and indirect bilirubin, urine bilirubin, urine urobilinogen, serum bile acid (TBA), gamma-glutamyl transpeptidase (γ-GT), and alkaline phosphatase (ALP). Elevation of these markers can occur due to hepatocyte degeneration and necrosis, bilirubin metabolism disorders, or intrahepatic bile stasis. In hemolytic jaundice, indirect bilirubin may increase.
(3) Indicators reflecting liver synthetic function mainly include albumin, pre-albumin, cholinesterase, and prothrombin time and activity. Long-term decreases in albumin, cholinesterase, and prothrombin activity, which cannot be corrected by vitamin K supplementation, suggest a gradual decrease in normal hepatocytes, poor hepatocyte synthetic function for proteins and coagulation factors, decreased liver reserve function, and poor prognosis.
(4) Indicators reflecting liver fibrosis mainly include type III procollagen (PⅢP), type IV collagen hyaluronic acid (HA), laminin (LN), etc. These markers can assist in the diagnosis of liver fibrosis and early cirrhosis.
(5) Indicators reflecting liver coagulation function: The liver can synthesize all coagulation factors except for factor III and the a-chain of factor a, playing a crucial role in maintaining normal coagulation function. In patients with liver disease, there is a reduction in the synthesis of coagulation factors, which can clinically manifest as bleeding from the gums, nasal mucosa, skin bruises, and severe cases may lead to gastrointestinal bleeding. Generally, factor VII is the first to appear and decrease the most, followed by factors II and X, and finally, factor V decreases the least.
