Noninvasive fetal RHD genotyping to guide targeted anti-D prophylaxis

CLAUSEN, FREDERIK BANCH; BARRETT, ANGELA NATALIE; COTORRUELO, CARLOS

VOX SANGUINIS

WILEY-BLACKWELL PUBLISHING, INC

Año: 2019 vol. 114 p. 386 - 393

0042-9007

BACKGROUND AND OBJECTIVES:Fetal RHD genotyping of cell-free fetal DNA from RhD-negative pregnant women can be used to guide targeted antenatal and postnatal anti-D prophylaxis for the prevention of RhD immunization. To assure the quality of clinical testing, we conducted an external quality assessment workshop with the participation of 28 laboratories.MATERIALS AND METHODS:Aliquots of pooled maternal plasma were sent to each laboratory. One sample was positive, and the second sample was negative for fetal RHD, verified by pre-workshop testing using quantitative real-time PCR (qPCR) analysis of RHD exons 4, 5, 7 and 10. Plasma samples were shipped at room temperature. A reporting scheme was supplied for data collection, including questions regarding the methodological setup, results and clinical recommendations. Different methodological approaches were used, all employing qPCR with a total of eight different combinations of RHD exon targets. The samples were tested blindly.RESULTS:Fetal RHD genotyping was performed with no false-negative and no false-positive results. One inconclusive result was reported for the RHD-positive sample, and four inconclusive results were reported for the RHD-negative sample. All clinical conclusions were satisfactory.CONCLUSION:This external quality assessment workshop demonstrates that despite the different approaches taken to perform the clinical assays, fetal RHD genotyping is a reliable laboratory assay to guide targeted use of Rh prophylaxis in a clinical setting.© 2019 International Society of Blood Transfusion.