The half-life of delta bilirubin is approximately how long?

• A. 1-2 weeks
• B. 2-3 weeks
• C. 4-6 weeks
• D. A few hours

Answer: (B)

Delta bilirubin stays in the bloodstream for a long time because it is covalently bound to albumin, so its clearance mirrors the turnover of albumin itself. Albumin has a half-life of about 20 days in humans, which translates to roughly two to three weeks for delta bilirubin. This long half-life explains why delta bilirubin remains elevated longer even after other bilirubin forms are cleared. The other timeframes don’t fit the binding behavior: a few hours is far too short for an albumin-bound pigment, and durations like one to two weeks or four to six weeks don’t align with the known rate of albumin turnover.