Bilirubin Blood Test

The bilirubin blood test is a medical laboratory test used to measure the levels of bilirubin in the blood. Bilirubin is a yellow pigment that is produced during the breakdown of hemoglobin, which is the protein in red blood cells that carries oxygen.

Purpose

The purpose of the bilirubin blood test is to:

• Diagnose and monitor liver disease, such as hepatitis or cirrhosis
• Diagnose and monitor hemolytic anemia, a condition where red blood cells are broken down faster than they can be made
• Check for blockages in the bile ducts, which can cause jaundice (a yellowing of the skin and eyes)
• Monitor the effectiveness of treatment for liver or hemolytic disorders

Types of Bilirubin Tests

There are two types of bilirubin tests:

• Total bilirubin test: measures the total amount of bilirubin in the blood, including both conjugated and unconjugated bilirubin
• Direct bilirubin test: measures the level of conjugated (direct) bilirubin in the blood
• Indirect bilirubin test: measures the level of unconjugated (indirect) bilirubin in the blood

How the Test is Performed

The bilirubin blood test is performed by:

• Taking a blood sample from a vein, usually in the arm
• Sending the blood sample to a laboratory for analysis
• Measuring the levels of bilirubin in the blood using a spectrophotometer or other specialized equipment

Normal Results

The normal results for bilirubin tests vary depending on the laboratory and the individual being tested. Generally:

• Total bilirubin: 0.1-1.2 mg/dL (1.7-20.5 μmol/L)
• Direct bilirubin: 0.0-0.3 mg/dL (0-5.1 μmol/L)
• Indirect bilirubin: 0.1-1.0 mg/dL (1.7-17.1 μmol/L)

Abnormal Results

Abnormal results may indicate:

• Liver disease, such as hepatitis or cirrhosis
• Hemolytic anemia
• Blockages in the bile ducts
• Other medical conditions, such as cancer or infection

Risks and Limitations

The bilirubin blood test is a relatively safe and simple procedure. However:

• There may be some discomfort or bruising at the site where the blood sample was taken
• Some individuals may experience dizziness or lightheadedness after the test
• The test may not detect all cases of liver disease or hemolytic anemia, and additional testing may be necessary for diagnosis