Angiogenic factors as diagnostic tests for preeclampsia: a performance comparison between two commercial immunoassays

OBJECTIVE: Placental growth factor and soluble Fms-like tyrosine kinase-1 may be potential diagnostic markers of preeclampsia. We compared performances of 2 immunoassays, the Triage placental growth factor assay and the Elecsys soluble Fms-like tyrosine kinase-1/placental growth factor ratio in diagnosing preeclampsia. STUDY DESIGN: A single site, case-control study of 44 patients with preeclampsia and 84 matched normal pregnant controls. Samples were collected at the time of diagnosis. Assays were performed according to product inserts. RESULTS: Both assays had optimal performance in diagnosing early-onset preeclampsia with area under the receiver operating characteristic curves of 0.99 (Triage: 100% sensitivity, 96% specificity; Elecsys: 64% sensitivity, 100% specificity for early-onset preeclampsia). Reassignment of the Elecsys cutoff for a positive test based on receiver operating characteristic curves increased sensitivity to 92%. CONCLUSION: Using product insert cutoffs, Triage appears to have greater sensitivity at only a small reduction in specificity compared with Elecsys in the diagnosis of early-onset preeclampsia. A different cutoff may improve Elecsys sensitivity.