Determination of serum total bilirubin is an important test in liver and biliary function tests, which is mainly measured by drawing blood for liver function tests. 1. Serum total bilirubin is usually measured by drawing blood, and its normal range is 5.13~22.24 μmol/L, which is important for clinical diagnosis of occult jaundice. Physiologic jaundice in newborns, without other discomforts, usually subsides in a week or so. Long-term alcohol consumption, strenuous exercise, etc. may also cause elevation of serum total bilirubin, which is a physiologic increase, and it can be recovered by itself after regulation. 2. Pathological increase in serum total bilirubin usually reflects abnormalities in liver function, mainly due to the dysfunction of bilirubin transport and uptake by liver cells caused by liver diseases, which in turn causes an increase in total bilirubin. Patients should consult the doctor in time to identify the cause of the disease and apply anti-inflammatory, hepatoprotective and anti-yellowing drugs under the doctor’s guidance. 3. Low serum total bilirubin may be caused by the lack of certain minerals or trace elements in the body, commonly found in iron deficiency anemia, etc., and patients may experience dizziness, weakness, fatigue and other symptoms. When the serum total bilirubin measurement is found to be abnormal, it is necessary for the doctor to combine the relevant indications for a comprehensive assessment, and can not rely on a single indicator to determine the condition, in order to avoid delaying the disease.