The effect of free fatty acid and bilirubin on a dye-binding assay for albumin with and without the presence of detergent

1. The effect of oleate and of bilirubin on the assay of albumin by a fluorescent dye-binding technique has been studied. 2. Using a solution of the dye 1-anilino-naphthalene-8-sulphonic acid (ANSA) in phosphate buffer and saline, competition of both oleate and bilirubin for dye-binding sites was observed. 3. Addition of sodium deoxycholate to the assay medium abolished the competition of oleate and bilirubin for ANSA-binding sites on albumin. 4. Deoxycholate itself reduced the magnitude of the fluorescent signal.