Bile acids are important components of bile and play an important role in fat metabolism. Bile acids are mainly found in the enterohepatic circulatory system and play a protective role through recirculation. Bile acid test, what is the significance of its abnormality? 1.Bile acid is synthesized in the liver from cholesterol and is the most abundant organic acid secreted by the liver into the bile, which is the main component of bile. 2.Bile acid has the function of promoting the digestion and absorption of fatty foods and fat-soluble vitamins and maintaining the soluble state of cholesterol in bile. Bile acid is combined with protein in the blood. The concentration of bile acids in the blood can increase after eating 90 and 120 points. 3.Serum bile acid is the only serological index that can respond to three aspects of hepatocyte anabolic function, secretion status and hepatocyte damage. 4, once the hepatocytes are diseased, the concentration of bile acids in the blood is likely to increase. 5, abnormal bile acid metabolism involves a variety of gastrointestinal diseases. Elevated serum bile acids during fasting are a result of the presence of absorption or secretion lesions in the liver, or portal shunts, and are one of the sensitive indicators of liver injury. The measurement of serum bile acid 2 hours after eating may be more sensitive than the measurement during fasting. 6, the diagnostic significance of increased serum bile acids must be combined with other liver function measurement values. It is generally believed that the measurement of bile acids has higher sensitivity and specificity for hepatobiliary diseases. It is commonly found in acute hepatitis, chronic hepatitis, cirrhosis, hepatocellular carcinoma, cholestasis, ethanol liver and toxic hepatobiliary diseases. Serum bile acids are more valuable when used for continuous monitoring of chronic liver diseases and are of high diagnostic value for the presence of chronic hepatitis, especially cirrhosis. 7. When hyperthyroidism or intestinal bile acid reabsorption is impaired, bile acid synthesis is enhanced, resulting in lower blood cholesterol. In the case of hypothyroidism, bile acid synthesis is weakened and blood cholesterol is increased. Disorders of bile acid metabolism may occur in hyperlipoproteinemia. Combined with other liver function tests, the diagnostic value can be improved. What is cholestasis? How does it occur? Scholars do not fully agree on the concept of cholestasis. Caseinologists define cholestasis as the accumulation of bile components seen within the hepatocytes and in the microbiliary system is called cholestasis. Clinicians, on the other hand, consider cholestasis as long as there is an accumulation of enzymes (alkaline phosphatase, gamma-transpeptidase) in the capillary bile ducts and an increase in bile acid concentration for therapeutic reasons. Cholestasis results from structural and functional disruption of any tissue involved in the production and secretion of bile. Cholestasis can manifest itself in mild, moderate or severe forms. In mild cases, there are only biochemical abnormalities without clinical symptoms, such as elevated γ-GT and mildly elevated AKP (alkaline phosphatase) and CH (cholesterol). Moderate cholestasis may have symptoms, such as malaise, itching, etc., and biochemically elevated Bil (bilirubin), ALT, and γ-GT. In severe cases, there is severe jaundice, which can lead to malnutrition, hepatocellular damage and liver failure, and even death.