Clinical Chemistry, Vol 34, 82-86, Copyright © 1988 by American Association for Clinical Chemistry

Immunoturbidimetry of urinary albumin: prevention of adsorption of albumin; influence of other urinary constituents

AJ Bakker
Department of Clinical Chemistry, Stichting Klinisch Chemisch Laboratorium, Leeuwarden, The Netherlands.

I describe a simple, rapid immunoturbidimetric assay for low concentrations of albumin in urine (2 to 260 mg/L). However, in this assay, the human serum albumin (HSA) in the standards binds nonspecifically to the polystyrene or glass tubes. This nonspecific binding cannot be prevented by adding bovine serum albumin (BSA) to standards, because the anti-HSA antibody cross reacts with BSA. Adding Triton X-100 (1 mL/L) to standards effectively prevents this nonspecific binding of HSA from standards to both polystyrene and glass tubes. High concentrations of compounds found in urine from normal and diabetic subjects do not interfere with this assay if pH extremes can be avoided. The between-day CV is 4.8% at means = 18.8 mg/L and 2.0% at means = 183.1 mg/L. Measurements by this immunoturbidimetric method (y) correlate well with those obtained by a radioimmunoassay (x): y = 1.078x - 0.141 mg/L (n = 98; r = 0.984) and with those obtained by a radial immunodiffusion method (x'): y = 1.026x' - 0.117 mg/L (n = 98; r = 0.983). Urinary excretion of albumin by 25 healthy, nondiabetic subjects was less than 8 micrograms/min.

The following articles in journals at HighWire Press have cited this article:

				A. J. Bakker, A. Bierma-Ram, H. Keidel, H. Syperda, and A. Zijlstra (Micro)Albuminuria: Antigen Excess Detection in the Roche Modular Analyzer Clin. Chem., June 1, 2005; 51(6): 1070 - 1071. [Full Text] [PDF]

				T. Makino Use of Microtiter Plates for Latex Agglutination Immunoassay of Serum Alpha2-Macroglobulin Ann. Clin. Lab. Sci., April 1, 2001; 31(2): 205 - 210. [Abstract] [Full Text] [PDF]