Clinical significance of microalbuminuria and evaluation of the micral-test

Abstract

Microalbuminuria is defined as excretion of albumin between 20 and 200 μg/min. Persistent microalbuminuria indicates a high probability of damage to the glomerular filtration capacity of the kidney and is of great diagnostic relevance: (a) in diabetes, for early diagnosis of diabetic nephropathy; (b) in patients with hypertension, as an indicator of end-organ damage associated with a lowered life expectancy; (c) in pregnancy, as a possible predictor of developing preeclampsia. For screening, a concentration of 20–200 mg/L of albumin in the first morning urine has been proven to be a suitable indicator. The Micral-Test is a test strip now available that makes a semiquantitative assessment of the albumin concentration in the urine at various levels (0, 10, 20, 50, 100 mg/L). Many studies have shown that the sensitivity and specificity of the test strip is 90% or higher in urine containing elevated albumin concentrations. Furthermore, it was shown that there is no influence on the measurement from interfering factors such as glucose concentration, pH value, ketonuria, storage of the sample, or bacterial contamination in the urine. The Micral-Test offers a simple, exact, and with respect to interference effects, a robust testing method for the semiquantitative assessment of albumin concentration in the urine.