Urinary albumin radioimmunoassay using a solid phase second antibody and solid phase albumin iodination.

The measurement of microalbuminuria in diabetics is now clinically important as a predictor of later overt clinical proteinuria, reflecting advanced diabetic nephropathy [l-3]. Urine albumin assays suitable for routine use in the clinical laboratory are therefore important. Measurement of microalbuminuria by current techniques including immunodiffusion [4] and electroimmunoassay [5] are time-consuming and the radioimmunoassays reported to date are cumbersome and difficult to set up [6,7]. This paper describes a radioimmunoassay for urinary albumin using a simple radioiodination technique and a solid phase second antibody separation. This sensitive and precise assay has been developed using commercially available reagents and is suitable for routine laboratory use.