Comparison of methods for determination of microalbuminuria in diabetic patients.

Microalbuminuria is an early marker of prognostic significance in diabetic renal disease. The aim of the present study was to compare methods which do not require radioactive markers for estimating microalbuminuria (20-300 mg l-1) with a radioimmunoassay for albumin estimation. Albumin concentrations of 329 diabetic patients were measured using two laser turbidimetric methods for albuminuria and proteinuria, two semiquantitative tests (Albusure and Albustix), and a routine albumin radioimmunoassay. The four methods in the order laser immunoturbidimetric for albuminuria, laser turbidimetric for proteinuria, Albusure and Albustix gave the following results: sensitivity 0.97, 0.93, 0.97 and 0.81; specificity 0.92, 0.88, 0.94 and 0.55; positive predictive value for microalbuminuria 0.83, 0.75, 0.85 and 0.42; negative predictive value for microalbuminuria 0.99, 0.97, 0.99 and 0.88. We suggest that both laser turbidimetric methods are reliable and can replace methods with radioactive markers, the same being true for the Albusure test.