The purpose of this study was to assess the clinical performance of SneakPeek® Early Gender Test (Gateway Genomics) for noninvasive prenatal testing (NIPT) of fetal sex. A multicenter-blinded study was conducted at four ultrasound clinics with maternal blood samples collected from pregnant women between 9 and 35 weeks of gestation. Circulating cell-free DNA was isolated from a micro-volume of maternal plasma and real-time quantitative PCR was performed to detect fetal DNA using a multi-copy sequence on the Y chromosome. An autosomal control gene was used to measure total cell-free DNA (maternal and fetal cfDNA). Sixty maternal plasma samples were tested twice, on different days, to assess the precision of SneakPeek.

Results:

• Cell-free DNA was detected in all maternal blood samples.
• Y-chromosome DNA was detected in all samples from women carrying a male fetus.
• SneakPeek correctly identified fetal sex in all samples.
• Assay precision data showed minimal variation and high reproducibility of results.
• Fetal sex for all samples was unknown prior to genetic testing and was confirmed via sonographic evaluation at the conclusion of the study. SneakPeek accuracy, sensitivity and specificity were each 100% for fetal sex identification. This blinded study showed that SneakPeek Early Gender Test is highly accurate for fetal sex determination in early pregnancy.