Urinalysis vs urine protein-creatinine ratio to predict significant proteinuria in pregnancy

To compare the urine protein-creatinine ratio with urinalysis to predict significant proteinuria (>or=300 mg per day).

A total of 116 paired spot urine samples and 24-h urine collections were obtained prospectively from women at risk for preeclampsia. Urine protein-creatinine ratio and urinalysis were compared to the 24-h urine collection.

The urine protein-creatinine ratio had better discriminatory power than urinalysis: the receiver operating characteristic curve had a greater area under the curve, 0.89 (95% confidence interval (CI) 0.83 to 0.95) vs 0.71 (95% CI 0.64 to 0.77, P<0.001). When matched for clinically relevant specificity, urine protein-creatinine ratio (cutoff >or=0.28) is more sensitive than urinalysis (cutoff >or=1+): 66 vs 41%, P=0.001 (with 95 and 100% specificity, respectively). Furthermore, the urine protein-creatinine ratio predicted the absence or presence of proteinuria in 64% of patients; urinalysis predicted this in only 19%.

The urine protein-creatinine ratio is a better screening test. It provides early information for more patients.