Measurement of Bilirubin-Albumin Binding. I. Comparative Analysis of Four Methods and Four Human Serum Albumin Preparations

摘要

Summary: Four methods for the measurement of bilirubin-albumin binding have been compared. Three of these, the fluorescent dye binding (Direct Yellow 7), Sephadex G-25 column chromatog-raphy, and the 2-(4-hydroxyazobenzene) benzoic acid (HBABA) dye binding methods demonstrate significant correlations of measured binding capacities for bilirubin over a range of bilirubin/albumin molar ratios. All three methods concurred in the demonstration that fresh adult human sera had a higher molar albumin binding capacity for bilirubin than the pruified human serum albumin preparations. The fluorescent dye binding and Sephadex column methods agreed most closely in' defining presumed deficiency in binding capacity. The HBABA dye binding method was less consistent and appeared to measure non-bilirubin binding sites on albumin in addition to bilirubin binding sites. The fourth method, the saturation index, yielded highly variable results as compared with the other methods because of an inherent excessive risk of laboratory error.Speculation: The four methods studied measure different aspects of bilirubin-albumin binding. Before clinical use, these methods may further require a systematic comparison utilizing sera from newborn infants. The effect of various pathophysiologic states and gestationsl age on the results of binding measured with these methods should be assessed. Neurobehavioral outcome of these infants in relation to the measured reserve binding capacity with these methods may establish clinical usefulness of any one or all of these methods.