Multicenter evaluation of the Micral-Test II test strip, an immunologic rapid test for the detection of microalbuminuria.

OBJECTIVE: To assess the performance of the Micral-Test II immunologic test strip for the detection of microalbuminuria, a multicenter evaluation in eight European study sites was performed. RESEARCH DESIGN AND METHODS: Using both the Micral-Test II test strip and the routine method for the determination of albumin concentration, we investigated 2,228 urine samples from diabetic patients. Additionally, interperson variability, color stability, and possible interfering factors (temperature, pH, leucocyturia, erythrocyturia, and drugs) were tested. RESULTS: For a cutoff concentration of 20 mg/l with respect to the routine methods, a sensitivity of 96.7% and a specificity of 71% were calculated for the Micral-Test II test strip. The negative predictive value was 0.95, and the positive predictive value was 0.78, with a prevalence of positive samples (laboratory method) of 52%. The interperson variability of color interpretation showed 93% concordant readings. The interference study showed an influence of oxytetracycline, leading to higher readings. There was no interference from pH. A sample temperature of < 10 degrees C led to lower readings. In the case of samples with massive leucocyturia and erythrocyturia that may delete the chromatographic process, waiting an additional 1-2 min is needed before reading. CONCLUSIONS: The results of the multicenter evaluation show that the Micral-Test II test strip permits an immediate and reliable semiquantitative determination of low albumin concentrations in urine samples with an almost user-independent color interpretation.

Light intensity adaptation of the phycobiliprotein content of the red alga Porphyridium.

In the unicellular red algae Porphyridium cruentum and P. aerugineum the phycobiliprotein content of the plastids is regulated by the applied energy fluence rate. Cells cultured at low energy fluence rates (220 µW cm(-2)) posses up to three times more phycobiliproteins than cells grown at high energy fluence rates (3200 µW cm(-2)). These values were obtained by direct measurement of the apoprotein of the phycobiliproteins. Transfer of cells from low to high energy fluence rates and vice versa results in an adaptation of the phycobiliprotein content to the new light conditions. This process starts immediately after the transfer of the cells and requires several days. On the other hand, the amount of the enzyme ribulose-1,5-bisphosphate carboxylase, which is also a prominent protein of the plastids of red algae, does not change significantly in response to differing fluence rates.