ATLANTA – A novel, noninvasive, “red dye on paper” diagnostic test allows for rapid screening and identification of preeclampsia at the point of care, according to findings from a prospective clinical study.
Of 343 women enrolled consecutively from a labor and delivery triage unit, 112 had a clinical diagnosis of preeclampsia. The diagnostic test – the Congo Red Dot (CRD) paper test – had an 86% rate of accuracy for detecting preeclampsia, which was superior to several other biochemical tests that were also evaluated, Dr. Kara Rood reported at the annual Pregnancy Meeting sponsored by the Society for Maternal-Fetal Medicine.
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Among the comparator tests, which were conducted using stored urine samples to strengthen the final diagnosis, were the laboratory “gold standard” CRD nitrocellulose test, as well as Protein/Creatinine ratio, and urine and serum placental growth factor (PlGF), sFlt-1, and urine sFlt-1/PlGF (uFP) ratio. Accuracy rates ranged from 60% to 83%, said Dr. Rood, a maternal-fetal medicine fellow at the Ohio State University Wexner Medical Center, Columbus.
The CRD point-of-care test was developed by researchers at Ohio State and Nationwide Children’s Hospital, also in Columbus, in an effort to reduce morbidity among expecting mothers and their unborn children. The current study is the first to test the affordable tool, and the findings promise to have an important impact on the health of women and children, she said.
Study subjects were consecutive women evaluated for preeclampsia at Wexner Medical Center. The CRD test was performed using 0.45 cc of fresh crude urine, and results were scored by trained clinical nurses at the bedside.
The average latency period between a positive paper-based CRD test and delivery was 14 days, which was significantly shorter than the interval for those who tested negative, Dr. Rood said.
Courtesy of the Ohio State University
The CRD test was developed based on previous findings by Dr. Irina A. Buhimschi of the Center for Perinatal Research in the the Research Institute at Nationwide Children’s Hospital and her colleagues, who discovered that preeclampsia may result from a collection of misfolded proteins that are identifiable in the urine of pregnant women. Congo Red is a dye used by pathologists to identify amyloid plaques in the brains of patients with Alzheimer’s disease, and it was found to bind and incorporate into the abnormally folded proteins in the urine of pregnant women with preeclampsia. The initial CRD test for preeclampsia had an 89% accuracy rate, according to preliminary findings published in 2014.
“This new point-of-care test is a more user-friendly version than the one in the [2014] publication, and can help identify preeclampsia even before clinical symptoms appear,” Dr. Buhimschi said in a press statement, which also noted that the research team is “currently investigating how each misfolded protein collection affects pregnant women. The answer might assist with developing an effective treatment or even preventing preeclampsia.”
Dr. Rood disclosed that concepts outlined during her presentation are the subject of patents and patent applications filed by Yale University and licensed to private entities for development and commercialization. Some of the study authors are named as inventors of the Congo Red Dot test.