Can Staining of Damaged Proteins in Urine Effectively Predict Preeclampsia?

OBJECTIVES To assess Congo red urine test in the first trimester for preeclampsia (PE) prediction. SAMPLE A Congo red test was developed with a cohort of 81 pregnant women in Bnai Zion hospital, Israel, at 26-41 weeks of gestation (12 PE cases). The test was then applied to a first-trimester cohort of 642 women at King's College Hospital, UK (105 subsequently developed PE, 21 early, i.e., <34 weeks; 537 controls). METHODS Urine samples were spotted onto nitrocellulose membranes, stained with Congo red, de-stained, dried and quantified with imager and densitometry. RESULTS At PE signs and symptoms, the detection rate (DR) was 93% and the false-positive rate (FPR) 4%. However, with first-trimester urine samples, the DR was 33.3%, 16.1% and 20% for early, late and all PE cases, respectively, at 12.8% FPR. The odds ratio (OR) for PE by Congo red alone (including adjusted OR) was superior to body mass index and mean arterial blood pressure (MAP) but inferior to previous PE and black ethnicity. Combining all five parameters generated an adjusted OR of 13.92 for PE (p < 0.001). CONCLUSION Congo red urine test at PE verifies the disorder. In the first trimester, it adds accuracy for PE prediction in obese, black women, who had previous PE and over-average MAP.