Rapid microalbuminuria screening in type 2 diabetes mellitus: simplified approach with Micral test strips and specific gravity

BACKGROUND: Microalbuminuria is known to be a harbinger of serious complications in type 2 diabetes mellitus. Since medical intervention at the onset of microalbuminuria can be critical in reducing these adverse outcomes, it is widely agreed that type 2 diabetic patients should be screened for microalbuminuria. The purpose of the present study is to evaluate Micral test strips in conjunction with a urine specific gravity determination as a rapid and accurate method for detecting microalbuminuria in type 2 diabetic patients. METHODS: In this prospective study, a total of 444 urine samples of type 2 diabetic patients were obtained from the ABCD study cohort for analysis. Urinary albumin concentrations were determined using Micral test strips and compared to results measuring albumin by the immunoturbidimetry method of timed collections. Urine specific gravity was measured by a standard urine dipstick. RESULTS: The performance characteristics of the Micral test strips for detecting microalbuminuria (30-300 mg albumin/24 h) were adequate but not optimal: sensitivity 88%, specificity 80%, positive predictive value 69%, negative predictive value 92%. A concomitant specific gravity determination was useful in indexing the magnitude of false negative and false positive readings by the Micral test strips. CONCLUSIONS: While the use of Micral test strips provides a rapid approach to detecting microalbuminuria in type 2 diabetic patients, this method has limitations. The simultaneous measurement of specific gravity is helpful in addressing some of the shortcomings of this screening test.