Cross-sectional diagnostic accuracy study of self-testing for proteinuria during hypertensive pregnancies: The UDIP study.

Abstract

OBJECTIVE: To determine the accuracy of self-testing for proteinuria during pregnancy. DESIGN: Diagnostic accuracy study. SETTING: Antenatal clinics, maternity assessment units and inpatient wards at three hospital sites. POPULATION OR SAMPLE: 345 pregnant women. METHODS: Pregnant women self-tested in-clinic for urinary protein using visually read dipsticks with samples then sent for laboratory estimation of the spot protein-creatinine ratio (PCR) (primary reference test). Secondary index tests included testing by antenatal healthcare professionals and an automated colorimetric reader. MAIN OUTCOME MEASURES: Sensitivity, specificity, negative predictive value, positive predictive value and likelihood ratios were calculated for self-testing (primary index test) along with healthcare professional and colorimetric testing compared to the primary reference test (PCR). RESULTS: 335/345 (97%) had sufficient data to be included in the analysis. Self-testing had a sensitivity of 0.71 (95% confidence interval [CI] 0.62-0.79) and a specificity of 0.89 (95% CI 0.84-0.92) compared to PCR. Sensitivity and specificity of testing by healthcare professionals and the colorimetric reader were similar: sensitivity 0.73 (95% CI 0.64-0.80) and 0.78 (95% CI 0.69-0.85), respectively; specificity 0.88 (95% CI 0.82-0.92) and 0.83 (95% CI 0.78-0.88), respectively. CONCLUSION: Pregnant women can visually read a dipstick for urinary protein with similar accuracy to antenatal healthcare professionals. Automated colorimetric testing was not significantly different, in contrast to some previous studies. Self-testing has the potential to form part of a self-monitoring regime in pregnancy.