Total bilirubin is one of the main indicators of liver function. It is the sum of unconjugated bilirubin and conjugated bilirubin in the blood, and if it is increased in the blood, it can cause the skin, mucous membranes, sclera and urine to be colored yellow, i.e. jaundice. Why do some patients have jaundice and others do not, when both have high total bilirubin? Because it is related to the concentration of total bilirubin, what is the normal value? How much above is considered high? The normal serum total bilirubin concentration is 2-17 μmol/L (0.1-1.0 mg/dl), and anything above this value is considered abnormal. When total serum bilirubin exceeds 34 μmol/L (2.0 mg/dl), the skin, sclera and mucous membranes appear yellow, which is called dominant jaundice; when total serum bilirubin is greater than 17 μmol/L (1.0 mg/dl) but less than 34 μmol/L (2.0 mg/dl), jaundice is not clinically manifested, and this condition is called occult jaundice. Elevated bilirubin can cause jaundice, whether it is dominant jaundice or recessive jaundice, it can cause certain harm to the human body, especially non-conjugated bilirubin has a special affinity for the nervous system and can cause nuclear jaundice, therefore, when you find your total bilirubin value is high, you must promptly go to a regular professional hospital for a comprehensive examination and treatment to avoid delaying your condition.