Serum total bile acids above 10.0 μmol/L are considered severe. The normal reference value for serum total bile acids is 0.1 to 10.0 μmol/L. Bile acids are important components of bile, derived from cholesterol, synthesized in the liver, and are key substances that promote intestinal digestion and absorption. Measurement of total bile acids can reflect the biochemical synthesis function of the liver and the secretion and uptake function of hepatocytes. Normally, the liver is able to synthesize bile acids as well as take up serum bile acids from the portal vein, but when liver damage occurs or the portal vein does not return properly, serum bile acids will be elevated. Elevated total bile acids are seen in: hepatocellular damage in hepatitis, cirrhosis, and hepatocellular carcinoma, biliary obstruction, and portal shunting. Also normally, a transient elevation of bile acids occurs after eating.