Quantitative Point of Care Tests for Timely Diagnosis of Early‐Onset Preeclampsia with High Sensitivity and Specificity

Preeclampsia is a heterogenous and multiorgan cardiovascular disorder of pregnancy. Here, we report the development of a novel strip-based lateral flow assay (LFA) using lanthanide-doped upconversion nanoparticles conjugated to antibodies targeting two different biomarkers for detection of preeclampsia. We first measured circulating plasma FKBPL and CD44 protein concentrations from individuals with early-onset preeclampsia (EOPE), using ELISA. We confirmed that the CD44/FKBPL ratio is reduced in EOPE with a good diagnostic potential. Using our rapid LFA prototypes, we achieved an improved lower limit of detection: 10 pg/ml for FKBPL and 15 pg/ml for CD44, which is more than one order lower than the standard ELISA method. Using clinical samples, a cut-off value of 1.24 for CD44/FKBPL ratio provided positive predictive value of 100% and the negative predictive value of 91%. Our LFA shows promise as a rapid and highly sensitive point-of-care test for preeclampsia.