A dipstick test combined with urine specific gravity improved the accuracy of proteinuria determination in pregnancy screening.

Abstract

Proteinuria screening using a semi-quantitative dipstick test of the spot urine in antenatal clinic is known to have high false-positive rates. The aim of this study was to assess availability of a dipstick test combined with the urine specific gravity for the determination of pathological proteinuria. A dipstick test was performed on 582 urine samples obtained from 283 pregnant women comprising 260 with normal blood pressure and 23 with pregnancy-induced hypertension. The urine protein (P) and creatinine (C) concentrations, specific gravity (SG), P/C ratio were determined, and compared with dipstick test results. The P concentration increased along the stepwise augmentations in dipstick test result. Frequencies of the urine samples with 0.265 or more P/C ratio were 0.7% with - dipstick test result, 0.7% with the ± result, 3.3% with the 1+ result, and 88.9% with the ≥2+ result. However, if the urine specific gravity was low, frequencies of the high P/C ratio were 5.0% with ± dipstick test result and 9.3% with the 1+ result. A dipstick test result of ≥2+ seems appropriate for a criterion of positive screening for pathological proteinuria in antenatal care. A dipstick test combined with the urine specific gravity may be useful for outpatient clinic screening.