The sFlt-1:PlGF Ratio in Women with Suspected Preeclampsia

The sFlt-1:PlGF Ratio in Women with Suspected PreeclampsiaTo the Editor: The article by Zeisler and colleagues (Jan.7 issue) 1 showed that a ratio of soluble fms-like tyrosine kinase 1 (sFlt-1) to placental growth factor (PlGF) of 38 or lower ruled out preeclampsia with a negative predictive value of 99.3% within 1 week in women with clinical suspicion of it.Critical in this study are the inclusion criteria used to define "impending" preeclampsia.In medicine, a definition of suspected preeclampsia is lacking, and the inclusion of patients at low risk may artificially increase the negative predictive value of a test by diluting the weight of false negative events.Only 41.5% of the women in the validation cohort had new-onset hypertension or an exacerbation of preexisting hypertension.Other clinical symptoms considered as inclusion criteria are often described in women with overt preeclampsia and used to define its severity, but in the absence of an elevated blood pressure, they lose their clinical importance.We wonder whether the simple inclusion of blood pressure instead of the angiogenic ratio in the evaluation of symptomatic patients would have yielded the same figure for the negative predictive value.