Replacing 24-h albumin excretion with a shorter collection period in preeclampsia

Objectives: To evaluate whether the gold standard of 24-h urinary albumin excretion in preeclamptic women could be substituted by a shorter collection period. Methods: From each woman, three spot, two 12-h, and one 24-h urine samples were collected. For each sample, urine albumin concentrations in milligram per liter were analyzed by the immunoturbidimetric method. The albumin concentrations in the spot and 12-h collections (day and night) were compared with the 24-h urine collection. Results: Albumin concentrations in both 12-h collections were fitted closely with the concentrations of the 24-h collection. The median difference between the 24-h collection and the day collection was 43 mg/L and the correlation coefficient was 0.96 (p < 0.0001). The median difference between the night collection and the 24-h collection was -31 mg/L and the correlation coefficient was 0.98 (p < 0.0001). Conclusion: The gold standard of 24-h urinary albumin concentrations in preeclamptic women can be substituted with a 12-h collection. Spot samples were weaker as compared to the 12-h collection.