Non-invasive fetal RHD genotyping for RhD negative women stratified into RHD gene deletion or variant groups: comparative accuracy using two blood collection tube types

For the deleted haplotype cohort, fetal RHD genotyping accuracy was comparable for samples collected in EDTA and BCT tubes despite higher cfDNA levels in the EDTA tubes. Capacity to predict fetal RHD genotype for maternal carriers of hybrid or pseudogene RHD variants requires stringent control of cfDNA levels. We conclude that fetal RHD genotyping is feasible in the Australian environment to avoid unnecessary anti-D immunoglobulin prophylaxis.