Which dye-binding reagent is specific but interfered by hemolysis and bilirubin?

• A. BCP
• B. BCG
• C. HABA
• D. Methyl Orange

Answer: (C)

Dye-binding assays measure albumin by a dye that binds preferentially to the protein, producing a color change that can be read spectrophotometrically. Among the reagents listed, HABA is the one that offers relatively specific binding to albumin, so the assay signal reflects albumin concentration more directly than with less selective dyes. However, any colored substances in the sample that absorb light at the assay’s measurement wavelength—such as hemoglobin from hemolyzed cells and bilirubin in jaundiced samples—can distort the color readout and cause interference. That combination—specific binding to albumin but susceptibility to interference from hemolysis and bilirubin—fits HABA best. The other reagents either are not as specific for albumin under typical conditions (or are not used for this purpose at all), so they don’t match the described property as well.