Polymer Enhancement of Automated Immunological Nephelometric Analysis, as Illustrated by Determination of Urinary Albumin

Abstract

Abstract We have developed a new automated immunonephelometric method for determination of albumin in urine, by exploiting the polymer-enhancing effect on the immunological reaction. The original continuous-flow manifold has been simplified and the reaction time shortened to about 3 min. The antiserum was diluted 100-fold in a solution (100 g/liter) of polyethylene glycol (av mol wt, 6000) and mixed with the prediluted sample in the continuous-flow system. The method is highly sensitive and is unaffected by high blank and (or) high absorbance values of the specimens. Day-to-day variation was 3.8-4.3% (CV). Accuracy, as estimated from recovery experiments, was also good. A comparative study of 176 urines with the single radial immunodiffusion technique showed a correlation coefficient of 0.994. We therefore suggest the new method for routine use for determination of urinary albumin, because it is fast, accurate, precise, and sensitive, and requires only small amounts of antiserum.