Diagnosis of preeclampsia and fetal growth restriction with the sFlt-1/PlGF ratio: Diagnostic accuracy of the automated immunoassay Kryptor®.

Objective: We aimed to characterize the diagnostic accuracy of the Kryptor® assay for sFlt-1 and PlGF in maternal serum samples of uneventful singleton pregnancies and subjects with preeclampsia (PE) and PE-related outcomes such as fetal growth restriction (FGR). Longitudinal reference ranges of the sFlt-1 and PlGF level in the course of normal pregnancies were generated.

Methods: A cohort of subjects with PE and PE-related outcomes including FGR in the third trimester was compared to a cohort of women with uneventful outcome. Serum levels of sFlt-1, PlGF level as well as the sFlt-1/PlGF ratio was analysed with the Kryptor® assay and compared between the case- and control groups. Cut-off values were generated and diagnostic accuracy examined.

Results: Longitudinal reference ranges of the sFlt-1 and PlGF level in healthy pregnancies were in line with those levels measured with other immunoassays. Comparison of the sFlt-1/PlGF ratio between PE-related outcomes including FGR or PE and healthy controls showed a high diagnostic accuracy with an area under the curve (AUC) of 0.917 for PE-related outcomes and 0.919 for PE.