Predictive blood group genetics in hemolytic disease of the fetus and newborn: a 10‐year review of a laboratory evaluation of amniotic fluid‐derived DNA

Abstract

Paternal RHD hemizygosity may be overestimated. Thus, we recommend that RHD zygosity be established by molecular analysis of the RHD breakpoint. Cultured amniocytes should be reserved for testing if the amniotic fluid-derived DNA is inconclusive due to PCR amplification failure. We use PCR-RFLP genotyping methods for RHCE*E/RHCE*e (Rh E/e), KEL1/KEL2 (K/k), FYA/FYB (Fy(a/b)), and JKA/JKB (Jk(a/b)).

DNA-based methods in the immunohematology reference laboratory

“…In the latter case, the mother need not be aggressively monitored and potentially can return to her primary care physician rather than be followed at a high risk clinic. Sources of fetal DNA include amniocytes (in amniotic fluid or cultured) and maternal plasma [18;19]. …”

Haemolytic disease of the fetus and newborn: advancements in precision and prevention

“…There are instances where the conventional zygosity testing targets are not present, thus laboratory assays must include molecular targets to detect the RHD gene in all of its configurations, including common silencing mutations, structural variants and rearrangements . If the paternal zygosity finds him to be hemizygous, additional testing such as cell‐free fetal DNA from the maternal blood sample or amniocentesis can be used to obtain fetal DNA for direct RHD genetic testing . Importantly, non‐invasive prenatal testing of the circulating cell‐free fetal DNA avoids the risk associated with amniocentesis.…”