What is the reason for low serum bilirubin in physical examination

When it comes to serum bilirubin, everyone may be unfamiliar with it. Serum bilirubin requires blood drawing for testing. The level of serum bilirubin is of great clinical significance in the diagnosis of neonatal jaundice and hemolysis. If the serum bilirubin level is too high, the newborn's skin will turn yellow. So what is the reason when the test report shows low serum bilirubin? Let's listen to the detailed explanation from a professional doctor.

Serum bilirubin is produced by hemoglobin released from the lysis of aging red blood cells in the body. It includes indirect bilirubin and direct bilirubin. Indirect bilirubin is transported to the liver through the blood and converted into direct bilirubin through the action of liver cells.

What are the causes of low serum total bilirubin?

1. Lack of zinc in the body leads to low serum total bilirubin

The human body may lack zinc due to anorexia or nutritional imbalance, and zinc deficiency is one of the reasons for low total bilirubin.

2. Iron deficiency anemia leads to low serum total bilirubin

Iron deficiency anemia can also lead to low total bilirubin in the human body. Iron deficiency anemia is anemia caused by the lack of iron in the human body, which affects the synthesis of hemoglobin. The symptom is a slightly yellow or pale complexion, but further examination is needed to determine whether it is iron deficiency anemia: red blood cell morphology, serum iron, and serum ferritin examination.

3. Detection errors lead to low serum total bilirubin. Detection errors can also cause low total bilirubin. At this time, the examiner can recheck the liver function to confirm whether it is an examination error.

4. Hepatitis B causes low serum total bilirubin

High total bilirubin may be caused by hepatitis B. Indirect bilirubin is mainly produced by the destruction of red blood cells, and the bilirubin that has not undergone glucuronidation in the liver is called indirect bilirubin. Indirect bilirubin can be converted into direct bilirubin through liver metabolism, excreted into the bile duct with bile, and finally excreted through feces.

5. Hemolytic jaundice leads to low serum total bilirubin

Hemolytic jaundice and hepatocellular jaundice can cause abnormal indirect bilirubin values.

6. What is the reference value of total bilirubin?

Reference value of total bilirubin: 3.4～17.1μmol/L. Total bilirubin is the sum of direct bilirubin and indirect bilirubin. Elevated total bilirubin is commonly known as jaundice.

Total bilirubin is mainly used to diagnose whether there is liver disease or bile duct abnormalities. The normal value of total bilirubin is between 3.4 and 20.5 μmol/L. 17.1-34.2 μmol/L can be regarded as latent jaundice; 34.2-170 μmol/L is mild jaundice; 170-340 μmol/L is moderate jaundice; and greater than 340 μmol/L is severe jaundice.

Generally speaking, low total bilirubin is not a big problem. It is recommended to check regularly and observe the situation. Total bilirubin is mainly used to diagnose whether there is liver disease or bile duct abnormality. The normal value of total bilirubin is between 1.7-17.1μmol/L. 17.1-34.2μmol/L can be regarded as latent jaundice; 34.2-170μmol/L is mild jaundice; 170-340μmol/L is moderate jaundice; and greater than 340μmol/L is severe jaundice.