CercaTest Red, a novel urine-based point-of-care test for the detection of preeclampsia

Abstract

Objectives Preeclampsia (PE) poses a serious threat to the health of the pregnant woman and her developing fetus due to the difficulty in diagnosing the condition. The disease can develop and worsen suddenly without noticeable signs and symptoms. Thus, there is an urgent need for a simple Point of Care Test (POCT) that improves accessibility to testing and can be used as an aid in the diagnosis of PE. CercaTest Red is a noninvasive detection kit for impending preeclampsia using urine from pregnant women. This is especially pertinent for women who have limited access to secondary/tertiary healthcare as those in remote settings, low-income countries or simply lack of out of hours laboratory services. Methods The kit employs an absorptive column that separates Congo red dye bound to urinary misfolded protein from pregnant women and unbound dye. When a solution of Congo red dye pre-mixed with urine is loaded onto the absorptive matrix in a detection cuvette, the presence (positive) or absence (negative) of misfolded proteins can be determined based on the color of eluate collected in the lower section of the cuvette. 190 and 937 pregnant women who were >18 years old at the gestational age of ≥20 weeks were enrolled for the feasibility and validation cohort, respectively. The consistency between CercaTest Red and clinical diagnosis of PE according to the American College of Obstetricians and Gynecologist (ACOG) Guidelines was analyzed using the kappa statistic. Results The POCT has a limit of detection (LoD) of human urinary misfolded proteins equivalent to 0.45 μM of denatured human serum albumin, with high reproducibility and stability. An accuracy of 96.84% for diagnosis of preeclampsia with a Kappa statistic of 0.746 (p < 0.001) was validated in a cohort of 937 subjects. Conclusion This test is easy to use, cost-effective and portable with short turnaround time and no laboratory instrument requirement. In the future, the test may have the potential to become quantitative using spectroscopy (Chinese Clinical Trial Registry No. ChiCTR1800017692).