A validated kit and flexible tube format enables laboratory processing on any qPCR machine.

A multi-target approach delivers an assay suitable for all populations and intra assay concordance for increased sensitivity.

Non-invasive prenatal testing (NIPT) of cell free fetal DNA (cffDNA) in maternal blood during pregnancy can be used to determine fetal Rhesus D blood group status. This means that RhD negative pregnant women can avoid receiving antenatal anti-D immunoglobulin if they are carrying a RhD negative baby and are not at risk of Hemolytic Disease of the Fetus and Newborn (HDFN).

Current practice is to provide antenatal anti-D prophylaxis at 28-30 weeks gestation, which means that about 40% of healthy RhD-negative pregnant women are exposed to a pooled human blood product that they do not need as their baby is also RhD negative1.

The Cell3™ Direct Fetal RhD Blood Group Genotyping kit predicts fetal RhD status with high accuracy and not only improves care for RhD-negative women but allows health services to apply a targeted approach to anti-D prophylaxis and conserve the use of an expensive product that can be in short supply.

Nonacus have developed the first commercially available, direct from plasma, non-invasive prenatal diagnosis (NIPD) kit for fetal RhD genotyping.

With no cffDNA extraction required and a simple real-time qPCR protocol, the Cell3™ Direct Fetal RhD Blood Group Genotyping kit delivers results direct from plasma in under three hours reducing technician time and providing a quicker, more cost-effective assay than previously available.

If, however, you already have high-throughput processing for extracted cffDNA set up in your laboratory or you are testing at 10-11 weeks when you need to maxmise sensitivity, the Cell3™ Direct Fetal RhD Genotyping kit can be still be used with extracted cffDNA.

There are now known to be several genetic causes for an RhD-negative phenotype, and these vary according to ethnic origin. In Caucasians a homozygous deletion of the RhD gene is the predominant cause, but in black Africans the RhD gene is intact but non-functional. This is known as the RhD-pseudogene (RhD-Psi).  It contains a 37 base pair insert in exon 4 and a nonsense mutation in exons 5+6, which may introduce stop codons preventing translation3. For an assay to be accurate across all populations, it must therefore target multiple exons in the RhD gene.

The Cell3™ Direct Fetal RhD genotyping kit targets sequences specific for exons 5, 7 and 10 of the RhD gene and can distinguish between RhD positive, RhD negative and RhD PSI genotypes making it suitable for any population.

Our direct from plasma protocol was compared with extracted cfDNA and results were demonstrated to be comparable using the same plasma sample (RhD positive, 24 weeks’ gestation).

Amplification plots of direct from plasma testing (see below) shows robust amplification of all targets: RhD exon 5 (blue), RhD exons 7 and 10 (green) and CCR5 (black).