Figure 1. Schematic representation of the possible results obtained using hypermethylated RASSF1A as a universal fetal marker when determining fetal sex by NIPD for a male fetus, female fetus, a case where no cell free fetal DNA is present and a case where no total cell free DNA is present.

Ticks represent the presence of amplified products from either the SRY assay or the RASSF1A assay. Crosses represent no amplification of SRY or RASSF1A amplicons.