An icteric specimen indicates elevated levels of which substance in the blood?

• A. Iron
• B. Creatinine
• C. Glucose
• D. Bilirubin

Answer: (D)

Icteric specimens are yellow because bilirubin, a bile pigment, is elevated in the blood. Bilirubin comes from the breakdown of hemoglobin in red blood cells. The liver normally processes and conjugates bilirubin so it can be excreted in bile; when bilirubin builds up—due to increased production (hemolysis), impaired liver conjugation, or blocked bile flow—the plasma appears yellow. So an icteric sample points to high bilirubin levels. The other substances listed don’t cause this yellow appearance: iron coloration, as well as creatinine or glucose, do not produce the icteric (yellow) tint in blood samples.