A comparison of spot urine protein-creatinine ratio with 24-hour urine protein excretion in women with preeclampsia.

INTRODUCTION: Proteinuria is an important diagnostic component of preeclampsia. We prospectively compared the results of spot urine protein-creatinine (P/C) ratio with 24-hour urine protein excretion in women with preeclampsia.

MATERIALS AND METHODS: A total of 81 pregnant women with preeclampsia were prospectively studied for proteinuria. Urine P/C ratio was determined in a spot mid-stream urine sample, and the amount of protein excretion was measured in 24-hour urine collected on the subsequent day. The correlation between the spot P/C ratio and 24-hour urine protein excretion was assessed. Diagnostic value of P/C ratio was expressed in terms of specificity and sensitivity. The receiver operating characteristic curve analysis was used to determine the best discriminator values of the spot urine P/C ratios for preeclampsia (proteinuria > or = 300 mg/24 h).

RESULTS: There was a strong correlation between the spot P/C ratio and 24-hour urine protein excretion (r = 0.84; P < .001). The optimal spot P/C ratio cutoff point was 0.20 for 300 mg/24 h of protein excretion (preeclampsia), with a sensitivity, specificity, positive predictive value, and negative predictive value of 91.2%, 87.8%, 94.4%, and 96.8%, respectively. The spot P/C ratios less than 0.19 yielded a sensitivity of 100% for exclusion of preeclampsia.

CONCLUSIONS: We found that there is a significant correlation between the spot urine P/C ratio and 24-hour urine protein excretion in women with preeclampsia. Urine P/C ratio could be used for exclusion of preeclampsia.