Bilirubin 160 in adults is serious. Bilirubin is mainly categorized as direct bilirubin, indirect bilirubin, and total bilirubin, but either 160 μmol/L is considered serious. When this occurs, it is important to first identify which bilirubin is most significantly elevated. When indirect bilirubin and total bilirubin are elevated, the main considerations are more destruction of red blood cells, hemolytic changes, and impaired liver function, with hepatocytes unable to synthesize enough direct bilirubin. When direct bilirubin and total bilirubin are elevated, biliary obstruction is often considered, resulting in the inability of bilirubin to be excreted into the intestine. Adult bilirubin 160μmol/L is a more serious level, and the cause must be identified as soon as possible and treated accordingly to avoid delays.