Congo Red Dot Paper Test for Antenatal Triage and Rapid Identification of Preeclampsia

Abstract

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.

Protein Misfolding during Pregnancy: New Approaches to Preeclampsia Diagnostics

“…The CRD paper test takes only about 5 minutes and demonstrates high accuracy in PE diagnosis. The authors report that the CRD paper test result can turn positive within 14 days before the clinical manifestation of PE [147]. However, the gestational age of women who took part in the research was generally between 28 and 38 weeks.…”

“…Moreover, qualitative (visual) detection based on the presence of the red spots on the filter is also doable. Later, Rood et al suggested the Сongo Red Dot (CRD) paper test as a simple, univocal, noninvasive clinical tool for rapid PE identification [147]. This modification of the detection approach is based on the fact that CR solution spotted on paper forms hydrogen bonds with cellulose and made a tight circle.…”

Cardiometabolic Risk Factors in Pregnancy and Implications for Long-Term Health: Identifying the Research Priorities for Low-Resource Settings

“…This may be due, in part, to insufficient power and sample size, and significant variations between clusters (20). Low cost urinalysis devices for proteinuria detection have also been developed and piloted (21)(22)(23), although evidence of impact on clinical endpoints is lacking.…”

On the Nature of Hydrodynamic Cavitation Process and Its Application for the Removal of Water Pollutants

“…Among other uses, CR possesses interesting applications in medicine tests for preeclampsia, determined affecting 15% of pregnancies and account for one quarter of antenatal admissions. 14 As the increased incidence of preeclampsia related to gestational weight gain has increased in the last decade, 15 as well as the need for a rapid and reliable test, the use of CR has increased in all around the United States. Once the test has been applied, the remaining are usually released to the wastewater generating a potential source of contamination.…”