Origins of Dye-Binding Methods for Measuring Serum Albumin

Methyl orange and hydroxybenzeneazobenzoic acid (HABA), 4 introduced in the 1950s, were the first dyes for measuring serum albumin (1 ). Methyl orange never gained acceptance in clinical laboratories because of its poor specificity, whereas HABA found limited use in the 1960s. In 1967, a trainee from Panama (Osvaldo Hernandez) at the Department of Clinical Pathology of the Medical College of Alabama wanted to present a report at the AACC annual meeting in Philadelphia and asked me (B.T.D.) to give him a "project." I told him to adapt Bartholomew and Delaney's bromcresol green (BCG) method for serum albumin (2 ) to the Technicon Auto-Analyzer. Bartholomew had changed the pH of Rodkey's BCG reagent from 7.15, at which it had an absorbance of approximately 2.5 absorbance units (3 ), to a pH of 3.8. There were peaks on the AutoAnalyzer recorder, but repeatability was poor because the AutoAnalyzer coils became covered with a blue sediment-the product of the reaction of BCG with albumin, which was not water-soluble. Addition of the detergent Brij-35 to the BCG reagent (the cure for most problems with AutoAnalyzer methods) turned the color of the BCG reagent to canary yellow and eliminated the blue sediment, but the peaks on the recorder persisted. That was the birth of the BCG albumin method. The presentation at the AACC meeting was received very well by the audience, and the chairman of the session asked, "Is this method really that simple?" Indeed it was.