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Stensrud M, Bævre MS, Alm IM, Wong HY, Herud I, Jacobsen B, de Vos DDJA, Stjern HE, Sørvoll IH, Barane JB, Bagås TE, Rasmussen M, Ulvahaug N, Wamstad V, Tomter G, Akkök CA. Terminating Routine Cord Blood RhD Typing of the Newborns to Guide Postnatal Anti-D Immunoglobulin Prophylaxis Based on the Results of Fetal RHD Genotyping. Fetal Diagn Ther 2023; 50:276-281. [PMID: 37379821 PMCID: PMC10614222 DOI: 10.1159/000531694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 06/09/2023] [Indexed: 06/30/2023]
Abstract
INTRODUCTION Targeted routine antenatal prophylaxis with anti-D immunoglobulin (Ig) only to RhD-negative pregnant women who carry RhD-positive fetuses (determined by fetal RHD genotyping) has reduced D-alloimmunization significantly when administered in addition to postnatal prophylaxis. Achieving high analysis sensitivity and few false-negative fetal RHD results will make RhD typing of the newborn redundant. Postnatal prophylaxis can then be given based on the result of fetal RHD genotyping. Terminating routine RhD typing of the newborns in cord blood will streamline maternity care. Accordingly, we compared the results of fetal RHD genotyping with RhD typing of the newborns. METHODS Fetal RHD genotyping was performed, and antenatal anti-D Ig was administered at gestational week 24 and 28, respectively. Data for 2017-2020 are reported. RESULTS Ten laboratories reported 18,536 fetal RHD genotypings, and 16,378 RhD typing results of newborns. We found 46 false-positive (0.28%) and seven false-negative (0.04%) results. Sensitivity of the assays was 99.93%, while specificity was 99.24%. CONCLUSION Few false-negative results support the good analysis quality of fetal RHD genotyping. Routine cord blood RhD typing will therefore be discontinued nationwide and postnatal anti-D Ig will now be given based on the result of fetal RHD genotyping.
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Affiliation(s)
- Monica Stensrud
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway
| | - Mette Silihagen Bævre
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway
| | - Inger Margit Alm
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway
| | - Ho Yi Wong
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway
| | - Ida Herud
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway
| | - Barbora Jacobsen
- Department of Immunology and Transfusion Medicine, St. Olavs University Hospital, Trondheim, Norway
| | | | - Helena Eriksson Stjern
- Department of Immunology and Transfusion Medicine, Akershus University Hospital, Lørenskog, Norway
| | | | - Janne Brit Barane
- Department of Immunology and Transfusion Medicine, Stavanger University Hospital, Stavanger, Norway
| | - Tonje Espeland Bagås
- Department of Immunology and Transfusion Medicine, Haukeland University Hospital, Bergen, Norway
| | | | | | - Vendula Wamstad
- Department of Laboratory Medicine, Vestre Viken Health Trust, Drammen, Norway
| | - Geir Tomter
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway
| | - Cigdem Akalin Akkök
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway
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Two Reliable Methodical Approaches for Non-Invasive RHD Genotyping of a Fetus from Maternal Plasma. Diagnostics (Basel) 2020; 10:diagnostics10080564. [PMID: 32764529 PMCID: PMC7460148 DOI: 10.3390/diagnostics10080564] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 07/30/2020] [Accepted: 07/30/2020] [Indexed: 12/27/2022] Open
Abstract
Noninvasive fetal RHD genotyping is an important tool for predicting RhD incompatibility between a pregnant woman and a fetus. This study aimed to assess a methodological approach other than the commonly used one for noninvasive fetal RHD genotyping on a representative set of RhD-negative pregnant women. The methodology must be accurate, reliable, and broadly available for implementation into routine clinical practice. A total of 337 RhD-negative pregnant women from the Czech Republic region were tested in this study. The fetal RHD genotype was assessed using two methods: real-time PCR and endpoint quantitative fluorescent (QF) PCR. We used exon-7-specific primers from the RHD gene, along with internal controls. Plasma samples were analyzed and measured in four/two parallel reactions to determine the accuracy of the RHD genotyping. The RHD genotype was verified using DNA analysis from a newborn buccal swab. Both methods showed an excellent ability to predict the RHD genotype. Real-time PCR achieved its greatest accuracy of 98.6% (97.1% sensitivity and 100% specificity (95% CI)) if all four PCRs were positive/negative. The QF PCR method also achieved its greatest accuracy of 99.4% (100% sensitivity and 98.6% specificity (95% CI)) if all the measurements were positive/negative. Both real-time PCR and QF PCR were reliable methods for precisely assessing the fetal RHD allele from the plasma of RhD-negative pregnant women.
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