Screening for microalbuminuria. A comparison of single sample methods of collection and techniques of albumin analysis.

To evaluate single-sample urine collections to determine their ability to screen patients for the presence of microalbuminuria. Microalbuminuria in patients with type I diabetes predicts the development of diabetic renal disease. Cross-sectional analysis of single-sample urine collection techniques (first morning void, random upright void) and methods of albumin analysis (RIA, reagent tablet) were compared with conventional 24-h urine collections (RIA). The study included 94 patients (45 males, 49 females; mean serum creatinine 88 microM) with type I diabetes, selected from a screened population of 301 patients from the University Hospital Subspecialty Clinics. A 24-hour urine collection RIA analysis for albumin revealed 36 normal patients (< 30 mg), 27 with microalbuminuria (30-300 mg), and 31 with albuminuria (> 300 mg). Random upright urine samples were more sensitive (RIA 89%, tablets 78%) for the detection of microalbuminuria than first morning void specimens (RIA 70%, tablets 60%). Specificity was > 80% with both random and first morning voids. Screening for microalbuminuria can be performed in the clinic by random upright single-sample urine collections. When reagent tablets were used, these results are available immediately. Patients who screen positive should be confirmed by 24-h or other timed urine collections.