Validation of the DCA® 2000 microalbumin:creatinine ratio urinanalyzer for its use in pregnancy and preeclampsia

Objective. To determine the accuracy of the DCA(R) 2000 albumin/creatinine ratio urinanalyzer (Bayer Corp., Elkhart, IN) in uncomplicated pregnancy and preeclampsia. Methods. This was a prospective observational study in a large teaching maternity hospital. Ninety one uncomplicated pregnant women and 100 women referred for assessment of de novo hypertension in pregnancy had albumin concentrations, creatinine concentrations, and albumin/creatinine ratios (ACR) compared between the DCA 2000 and the laboratory gold standard assays (Dade Dimension(R) clinical chemistry autoanalyzer), for both early morning urines (EMU) and 24-hr urine collections. Results. The interassay and intra-assay variability for the DCA 2000 were less than 5.1%. In uncomplicated pregnancy the mean difference in ACR between the DCA 2000 and the laboratory assay was 0.08 mg/mmol (SD 0.28; 95% limits of agreement, -0.47, 0.63) for EMU and 0.06 (SD 0.23; 95% limits of agreement, -0.39, 0.51) for 24-hr samples. In the hypertensive cohort the ACR mean differences were -0.82 (SD 7.13; 95% limits of agreement, -14.79, 13.15) for EMU and -0.76 (SD 4.14; 95% limits of agreement, -8.87, 7.35) for 24-hr samples. The mean differences between assays in the hypertensive group had broader 95% limits of agreement due to greater variability in the samples with high albumin concentrations ( > 40 mg/L). Conclusions. The DCA 2000 is accurate for the measurement of albumin creatinine ratios in the uncomplicated pregnant population. In the hypertensive population the DCA 2000 remains accurate though when the albumin concentration is greater than 40 mg/L the 95% limits of agreement are broader. We would recommend that all other automated urinalysis devices be validated by similar protocols to allow meaningful comparisons of accuracy.