Clinical Chemistry, Vol 27, 322-325, Copyright © 1981 by American Association for Clinical Chemistry

Four methods for determining albumin in azotemic sera evaluated

PF Gulyassy, TA Depner and WK Ma

The methods most commonly used for determination of albumin in serum depend on its binding of dyes. The binding of many drugs as well as of several dyes is impaired in azotemic sera from patients with renal failure. We therefore evaluated four methods used to measure albumin concentration in sera of patients with various degrees of renal failure, comparing results with those by the most specific method, radial immunodiffusion. The automated bromcresol green, manual immediate bromcresol green, cellulose acetate electrophoresis, 2-(4'- hydroxyazobenzene)benzoic acid binding, and Na2SO3 precipitation/biuret methods were evaluated. The correlations with results of radial immunodiffusion for azotemic sera differed from method to method but were approximately the same for each method, as in previous published reports for samples from a heterogeneous population of patients. The ratios of serum albumin concentration by these methods to albumin concentration as measured by radial immunodiffusion ranged from 0.96 to 1.13 for 29 to 41 normal and azotemic sera, but none of the ratios showed any variation beyond random scatter over a range of serum creatinine from 6.0 to 180 mg/L. Thus the choice of method to apply to azotemic sera will depend on the relative importance of accuracy, speed, cost, and technical complexity.