Fetal RhD genotyping by real time quantitative PCR in maternal plasma of RhD-negative pregnant women from the Sahel of Tunisia.

OBJECTIVE: The aim of this study was to evaluate the diagnostic value of RhD fetal genotyping from the plasma of RhD-negative pregnant women.

METHODS: We analysed the plasma samples of 65 pregnant women. DNA quantification was done using real time quantitative PCR (RQ-PCR) in multiplex targeting multiple RhD exons 5, 7 and 10, with a standardized pool of plasmid calibrators. Results were compared with serological analysis of cord blood after delivery.

RESULTS: Fetal RhD status was predicted with 95.38% accuracy from maternal plasma of pregnant women in the 11(th) to 40(th) weeks of gestation. One false positive but no false negative results were found. Thus the sensitivity of the assay was 100% and the specificity was 94.44 %.

CONCLUSION: The present data demonstrates that the fetal RhD genotyping approach could be achieved efficiently with RQ-PCR for RhD-negative tunisian pregnant women.