Measurement of urinary microalbumin using enzyme-linked immunosorbent assay and latex agglutination method

Minn, Doh Sik; Park, Ile Kyu; Chae, Jeong Don; Lee, Woong Soo; Kim, Think You

Abstract

BACKGROUND: Microabluminuria is defined as the amount of albumin in urine that is excreted above the normal but cannot be detected by the standard clinical dipstick test, and is used as a predictor for clinical diabetic nephropathy. It is therefore important to diagnose microalbuminuria with a sensitive, rapid and simple method. We developed a home-made ELISA for measuring microalbumin and a home-made latex agglutination method for diagnosing microalbuminuria. The aim of this study is to evaluate these methods and to evaluate the possibility of application for clinical uses.
METHODS
We collected 24 hour urine samples from 86 patients at Hanyang University Kuri Hospital from January 1999 to April 1999. The principle of the ELISA is a double antibody sandwich technique. The latex agglutination method used rabbit anti-human albumin and latex bead.
RESULTS
Within-run precisions of ELISA were 8.3% in low concentrations and 7.7% in high concentrations. Between-run precisions were 8.7% and 7.8%, respectively. The correlation coefficient between ELISA and RIA in samples from 80 patients was 9.4(P < 0.01). The sensitivity and specificity of the latex method were 90% and 97%, respectively.
CONCLUSIONS
The home-made ELISA was a sensitive and relatively simple method for quantitation of microalbumin and correlated highly with the RIA. Therefore, this ELISA may replace RIA and can be used in other clinical uses. The latex agglutination method is simple, rapid, inexpensive and sensitive and correlated highly with the RIA. Clinically, this method may help patients and physicians in screening microalbuminuria.