Assessment of a new dipstick test in screening for microalbuminuria in patients with hypertension☆

The prevalence of elevated urinary albumin levels is significantly greater in hypertensive than in normotensive subjects. To determine the sensitivity and specificity of a new dipstick test for microalbunimuria (the Micral-Test), 171 hypertensive patients were studied at a union-sponsored hypertension treatment program. Sensitivity, specificity, predictive values, and correlation coefficients between urinary albumin concentration results obtained by the Micral-Test and by nephelometry were determined in three urine samples. Sensitivity values of the Micral-Test, compared with 24-h nephelometry, were 81%, 75%, and 92% in a 24-h, overnight, and random sample, respectively. Specificity values were 89%, 90%, and 63% in the three samples, respectively. Positive predictive value ranged from 41% to 67%, whereas negative predictive value ranged from 93% to 97%. Correlation coefficients between the logarithms of albumin concentrations obtained from the three different urine specimens using nephelometry fell between 0.71 and 0.78, whereas those obtained with the Micral-Test fell between 0.49 and 0.71, and across techniques, 0.29 to 0.53 (all P < .001). Results obtained with both nephelometry and the Micral-Test using overnight and random urine collections approximated those obtained with 24-h collection. These results, coupled with the ease and convenience of both specimen collection and the Micral-Test itself, support the use of the test as a valuable screening tool for microalbuminuria in patients with hypertension.