A Comparative Evaluation of Various Methods for Microalbuminuria Screening

Abstract

Background/Aims: Microalbuminuria is a marker of abnormal vascular response and a predictor of cardiovascular morbidity and mortality. We evaluated a new quantitative office-based method to assess urinary albumin excretion (UAE) and compared it to other established methods. Methods: Spot urine samples from 165 patients were analyzed at a single study site using the HemoCue system, Clinitek Microalbumin, and Chemstrip Micral test, as well as at a central laboratory, where UAE and creatinine levels were measured. The central laboratory UAE values were used as reference. We evaluated the validity of the HemoCue results and compared them to the respective data for the laboratory albumin-to-creatinine ratio (ACR). Additionally, we assessed, diagnostic sensitivity, specificity, and positive and negative predictive values of all four methods, as well as the reproducibility of the HemoCue measurements. Results: Linear regression analysis demonstrated a good correlation for the HemoCue system (y = 0.9978x – 1.0217, R² = 0.904) and ACR (y = 0.0815x + 0.3373, R² = 0.784). Sensitivity and specificity for microalbuminuria diagnosis were 92 and 98% for HemoCue, 73 and 96% for ACR, 100 and 81% for Clinitek Microalbumin, and 70 and 83% for Chemstrip Micral dipstick, respectively. The correlation coefficient of duplicate HemoCue measurements was r = 0.98 (p < 0.001). Conclusions: The HemoCue system for microalbuminuria detection was as accurate and precise as laboratory ACR estimations. Its diagnostic performance was much better than that of widely used dipstick methods.