Bilirubin is a yellow pigment formed during the breakdown of red blood cells.

Direct (conjugated) bilirubin is processed by the liver and excreted into bile.

Clinical uses include:

Detecting obstructive jaundice (bile duct blockage).

Assessing liver diseases such as hepatitis, cirrhosis, or cholestasis.

Differentiating between hemolytic jaundice (indirect bilirubin) and obstructive/hepatic jaundice (direct bilirubin).

The test is performed using a blood sample, often alongside Total Bilirubin and Indirect Bilirubin.

Analyte: Direct (conjugated) bilirubin in blood serum.

Normal Range: ~0.0 – 0.3 mg/dL (varies slightly by lab).

Elevated Levels:

May indicate bile duct obstruction, gallstones, hepatitis, cirrhosis, or liver injury.

Often associated with dark urine and pale stools due to impaired bile flow.

Clinical Use:

Differentiates type of jaundice.

Assesses liver and biliary tract function.

Guides further diagnostic imaging and treatment decisions.