Accuracy of the 24-h urine protein excretion value in patients with preeclampsia: correlation with instant and 24-h urine protein/creatinine and albumin/creatinine ratios

The aim of this study was to determine the accuracy of the 24-h urine collection in preeclamptic pregnant women. This study included 65 singletons with preeclampsia and 53 singleton patients in a control-matched group. The ratio of inaccurate 24-h urine collection was measured by calculating expected urine creatinine excretion according to the proportion of pre-pregnancy weight and the lean body mass (LBM) of the patients. Comparisons were made between the accurately-collected 24-h urine protein excretion rates and the instant and 24-h urine protein/creatinine (P/Cr) and albumin/creatinine (A/Cr) ratios. Twenty-four-hour urine collection used to diagnose patients with preeclampsia was incorrectly collected 15-73.5% of the time among the patients and the control group. Instant and 24-h urine P/Cr and A/Cr ratios were correlated with total 24-h proteinuria among the patients in whom urine was collected correctly. Considering the 24-h urine P/Cr ratio, rather than the 24-h urine protein excretion value, is a better way to diagnose preeclampsia.IMPACT STATEMENT What is already known on this subject? Twenty-four-hour urine collection is considered as the gold standard of diagnosing proteinuria in preeclampsia, in case of the correctly collected. What do the results of this study add? Generally, in the literature the correctness of 24-h proteinuria is not questioned. However, it is actually quite important in daily practice to make the correct diagnosis of the proteinuria not to misdiagnose preeclampsia.