Diagnostic Accuracy of Spot Urine Protein to Creatinine Ratio for Estimation of Significant Proteinuria in Patients of Preeclampsia

Abstract

To determine diagnostic accuracy of spot urine protein to creatinine ratio (PCR) for estimation of significant proteinuria in patients of preeclampsia based on 24-hour urine protein. METHODS: This cross-sectional validation study was conducted at Gynae B unit, Lady Reading Hospital, Peshawar from July 2014 to December 2014. Out of 253 patients, 222 women were finally enrolled as per inclusion and exclusion criteria by using non-probability convenient sampling technique. After taking proper history and calculating period of gestation, blood pressure was measured using standard sphygmomanometer while urinary protein by urine dipsticks. Following standard protocol, urine was collected for 24 hours followed by spot midstream urine. Samples were analyzed for urine protein and creatinine. 24 hours urinary protein level ≥300 mg/day and spot urine PCR was ≥3 mg/mmol was considered significant proteinuria. SPSS v 16.0 was used a statistical instrument. RESULTS: Out of 222 patients with preeclampsia, 24-hours urinary protein level estimation was ≥300 mg/day in 179 (80.6%) cases and <300 mg/day in 43 (19.4%) cases. Spot urine PCR was ≥3 mg/mmol in 175 (78.8%) cases and <3 mg/mmol in 47 (21.2%) cases. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy of spot urine PCR against 24-hours urinary protein level estimation was 95.5%, 90.6%, 97.7% 82.9% and 94.5% respectively. CONCLUSION: In our study, spot urinary protein/ creatinine ratio shows a high sensitivity, specificity, PPV, and NPV (at a cut off value >0.3 mg/mmol). This test can be regarded as a reliable investigation among pre-eclamptic patients.