Clinical Laboratory Science Practice Test 2026 – Urinalysis and Body Fluids

Xanthochromia occurs when red blood cells in the CSF break down over time, producing bilirubin, a pigment that gives the fluid a yellow color. Bilirubin comes from the breakdown of heme in hemoglobin, which is a protein, so the presence of xanthochromia is most closely tied to elevated protein and its breakdown products in the CSF. Other substances listed do not produce this pigment-related discoloration.