Congo red test for identification of preeclampsia: Results of a prospective diagnostic case-control study in Bangladesh and Mexico

Abstract

Background Misfolded proteins in the urine of women with preeclampsia bind to Congo Red dye (urine congophilia). We evaluated a beta prototype of a point-of-care test for the identification of urine congophilia in preeclamptic women. Methods Prospective diagnostic case-control study conducted in 409 pregnant women ( n = 204 preeclampsia; n = 205 uncomplicated pregnancies) presenting for delivery in two tertiary level hospitals located in Bangladesh and Mexico. The GV-005, a beta prototype of a point-of-care test for detecting congophilia, was performed on fresh and refrigerated urine samples. The primary outcome was the prevalence of urine congophilia in each of the two groups. Secondary outcome was the likelihood of the GV-005 (index test) to confirm and rule-out preeclampsia based on an adjudicated diagnosis (reference standard). Findings The GV-005 was positive in 85% of clinical cases (83/98) and negative in 81% of clinical controls (79/98) in the Bangladesh cohort. In the Mexico cohort, the GV-005 test was positive in 48% of clinical cases (51/106) and negative in 77% of clinical controls (82/107). Adjudication confirmed preeclampsia in 92% of Bangladesh clinical cases (90/98) and 61% of Mexico clinical cases (65/106). The odds ratio of a urine congophilia in adjudicated cases versus controls in the Bangladesh cohort was 34 . 5 (14 . 7 – 81 . 1) ( p <0 . 001) compared to 4 . 2 (2 . 1 – 8 . 4; p <0 . 001) in the Mexico cohort. Interpretation The GV-005, a beta prototype of a point-of-care test for detection of urine congophilia, is a promising tool for rapid identification of preeclampsia. Funding Saving Lives at Birth.

The effectiveness of the Congo Red Dot paper test in hypertensive disorders of pregnancy: A systematic review and meta-analysis

“…Five studies reported that CRDPT can be used to verify HDP. In a study by Bracken et al, 204 were pre-eclamptic and 205 normotensive women, the CRDPT was found to be effective in 155 and 50 respectively ( 30 ). In a study by Dobert et al which included 46 pre-eclamptic and 2,094 pregnant normotensives, the CRDPT was found to be effective in 2 and 4 respectively ( 27 ).…”

“…Even though there are studies which found CRDPT to be effective in the detection of PE (21,22,(30)(31)(32), most of these studies had sampling bias (21,22,31,32), whereby higher sampling probability Evaluating sensitivity and specificity of CRDP test in detection of hypertensive disorder of pregnancy. 5, 6).…”

Proteomic Analysis of Maternal Urine for the Early Detection of Preeclampsia and Fetal Growth Restriction

“…Their study also reported misfolded proteins in the urine of women with preeclampsia bound to Congo Red dye (urine congophilia or affinity for the amyloidophilic dye Congo Red) [37]. Ultimately, their study reported promising results from a prototype point-of-care test for the detection of urine congophilia [38]. A review by Navajas et al found nine publications from 2008 to 2020 that observed 132 proteins that were differently expressed in urine in PE cases compared to controls [22].…”

New approaches in predicting and diagnosing preeclampsia: Congo Red Dot Paper Test (Review)

“…The latest results from a prospective diagnostic casecontrol study in Bangladesh and Mexico conducted by Bracken et al (40) were published in January 2021. The survey evaluated the success of a beta prototype test in identifying misfolded proteins in the urine of women suffering from PE.…”