Random urine protein to creatinine ratio as a diagnostic method of significant proteinuria in pre-eclampsia

Because of the importance of pre-eclampsia and proteinuria in pregnancy, a faster and simpler diagnostic method is needed.

To compare random urine protein to creatinine ratio (p:c ratio) with 24-h urine protein excretion rate in pregnant women with a suspicion of pre-eclampsia.

The study was conducted on 100 pregnant women with gestational ages of >or=20 weeks; 50 patients were suspected of having pre-eclampsia and 50 were healthy pregnant women. A random urine sample for p:c ratio determination and a 24-h urine sample for protein measurement were obtained.

All women suspected of having pre-eclampsia had significant proteinuria. The single-voided p:c ratio demonstrated a sensitivity of 94% with a specificity of 96% at the cut-off>or=0.2 mg/mg. There was strong correlation between the two methods in this group (r=0.70, P<0.001, R2=49%). Using the same cut-off in the pregnant women who were not thought to have pre-eclampsia, the sensitivity of the test (p:c ratio) was 29% and the specificity was 87%. Pearson's correlation coefficient was 26 (P<0.06). Negative predictive value and positive predictive value were 34 and 83%, respectively.

There is a strong correlation between 24-h urine protein excretion and single-voided urine p:c ratio in women suspected of having pre-eclampsia. A single-voided p:c ratio of >or=0.2 mg/mg is highly predictive for significant proteinuria. However, this test was not found to be a reasonable alternative to 24-h urine collection; and it must be followed by 24-h urine collection in a clinically suspect patient with a p:c ratio of <0.2 mg/mg.