Bilirubin

Definition

Bilirubin is a yellow-orange pigment produced when heme from red blood cells is broken down. Elevated bilirubin (hyperbilirubinemia) causes jaundice. Yellowing of the skin, sclera, and mucous membranes.

Types

• Indirect (unconjugated): Fat-soluble, bound to albumin, not yet processed by liver.
• Direct (conjugated): Water-soluble, processed by liver, excreted in bile.
• Total: Sum of indirect + direct.

Normal Values

Total bilirubin: 0.1 to 1.2 mg/dL. Direct: 0 to 0.3 mg/dL.

Clinical Implications

High indirect: hemolysis, neonatal physiologic jaundice. High direct: biliary obstruction (gallstones, tumor), hepatitis, cirrhosis. In neonates, bilirubin greater than 15 to 20 mg/dL increases risk of kernicterus (bilirubin encephalopathy).

Nursing Interventions

In neonates, place infant under phototherapy with eyes shielded and diaper only; increase feeding frequency; monitor bilirubin levels and temperature. In adults with jaundice, assess pruritus, monitor liver enzymes, and support nutrition.

NCLEX Relevance

Classic neonatal question: phototherapy for hyperbilirubinemia, protecting eyes and skin.