Cell-free DNA analysis in maternal blood: comparing genome-wide versus targeted approach as a first-line screening test.

Objectives: To evaluate the failure rate and performance of cell-free DNA (cfDNA) testing as a first-line screening method for major trisomies, performed by two laboratories using different analytical methods: a targeted chromosome-selective method (Harmony prenatal Test) versus a genome-wide (GW) massively parallel sequencing method (HB-cfDNA test), and to evaluate the clinical value of incidental findings for the latter method.

Methods: CfDNA testing was performed in 3137 pregnancies with the Harmony prenatal Test and in 3373 pregnancies with the HB-cfDNA test. Propensity score analysis was used to match women between both groups for maternal age, weight, gestational age at testing, fertilization, rate of twin pregnancies and that of aneuploidies.