Serum Bilirubin Total / Direct / Indirect

The Serum Bilirubin test measures the amount of bilirubin in the blood. Bilirubin is a yellow pigment produced during the normal breakdown of red blood cells. This test helps evaluate liver function, detect jaundice, and monitor liver or bile duct disorders.

Types of Bilirubin Measured:

1. Total Bilirubin – The sum of direct and indirect bilirubin

2. Direct (Conjugated) Bilirubin – Bilirubin processed by the liver and ready for excretion

3. Indirect (Unconjugated) Bilirubin – Bilirubin not yet processed by the liver

• To diagnose jaundice

• To evaluate liver function

• To detect liver diseases like hepatitis or cirrhosis

• To check for hemolytic anemia

• To monitor response to liver treatments

Sample Required:
A blood sample

Fasting Required:
Usually fasting for 8–12 hours is recommended.

• Serum Bilirubin – Normal Reference Ranges

  Type	mg/dL (per deciliter)	µmol/L (per liter)
  Total Bilirubin	0.3 – 1.2 mg/dL	5.1 – 20.5 µmol/L
  Direct Bilirubin	0.1 – 0.3 mg/dL	1.7 – 5.1 µmol/L
  Indirect Bilirubin	0.2 – 0.9 mg/dL	3.4 – 15.4 µmol/L

• Elevated Total & Indirect Bilirubin: May indicate hemolysis or Gilbert’s syndrome

• Elevated Direct Bilirubin: Often linked to liver or bile duct blockage (e.g., hepatitis, gallstones)

• High Both: May suggest mixed liver dysfunction