Background Proteins in the urine of women with preeclampsia (PE) bind Congo Red dye (urine congophilia). We sought to determine the diagnostic performance of a paper-based point-of-care test detecting urine congophilia for rapid triage and diagnosis of PE. Methods Prospective cohort study conducted in 346 consecutive pregnant women evaluated for PE in the Labour and Delivery triage unit at our institution. The Congo Red Dot (CRD) Paper Test (index test) was performed on fresh urine samples. The CRD Paper Test results were compared to an expert adjudicated diagnosis in each case. The accuracy of the CRD Paper Test was also compared to urine and serum analytes (placental growth factor and soluble fms-like tyrosine kinase-1) previously proposed as diagnostic aids for PE. Findings During the first triage visit, 32% (112/346) of women received a clinical diagnosis of PE. Yet, 63% (217/346) were admitted for in-patient diagnostic work-up or delivery. The CRD Paper Test was positive in 25% (86/346) of the cases. Adjudication confirmed PE in 28% (96/346) of all cases. The CRD Paper Test outperformed measured serum and urine markers (80·2% sensitivity, 89·2% specificity, 92·1% negative predictive value, 86·7% accuracy). The pre-test, positive and negative post-test probabilities were 27·7%, 74·0%, and 8·0%, respectively. Of women who were discharged undelivered, 38% (133/346) had at least one additional triage visit and the interval between the last negative and first positive CRD Paper Test was 12 (interquartile range, [5–34]) days. Interpretation The CRD Paper Test is a simple, non-invasive, “sample-in/answer-out” point-of-care clinical tool for rapid identification of PE. Funding Saving Lives at Birth Program and NICHD.

flavanol (HFC) or low-flavanol chocolate (LFC). A total of 30 g of chocolate was consumed daily for 12 weeks and women were followed until delivery. Uterine artery Doppler pulsatility index (UtA PI), reported as multiple of medians (MoM) adjusted for gestational age, was assessed at baseline and 12 weeks after randomization. Preeclampsia, gestational hypertension, placenta weight, and birthweight were also evaluated. RESULTS: One hundred twenty nine women were randomized at a mean gestational age of 12.4 AE 0.6 weeks with a mean UtA PI of 1.4 AE 0.4 MoM. Although adjusted UtA PI significantly decreased from baseline to 12 weeks in the 2 groups (<0.0001), the difference between the 2 groups was not significant (p¼0.16). At 12 weeks, we observed no significant difference between HFC and LFC groups in the rate of preeclampsia (4.7% vs 3.1%, p¼0.49) and gestational hypertension (6.2% vs 12.5%, p¼0.56). Placental weight (466 vs 464 grams, p¼0.93) and birthweight (3348 vs 3215 grams, p¼0.07) were comparable between the two groups. CONCLUSION: Compared with low-flavanol chocolate, daily intake of 30g of high-flavanol chocolate did not improve placental function, placental weight and the risk of preeclampsia. Nevertheless, the marked improvement of the pulsatility index observed in the 2 chocolate groups might suggest that chocolate effects are not solely and directly due to flavanol content.