Premium
Resolving variable maternal D typing using serology and genotyping in selected prenatal patients
Author(s) -
Clarke Gwen,
Han Judith,
Berardi Philip,
Barr Gerri,
Cote Jacqueline,
Fallis Robert,
Alport Ted,
Lane Debra,
Petraszko Tanya,
Ochoa Gorka,
Goldman Mindy
Publication year - 2016
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/trf.13798
Subject(s) - genotyping , serology , typing , medicine , genotype , immunology , antibody , genetics , biology , gene
BACKGROUND RhIG prophylaxis for D– pregnant women prevents hemolytic disease of the newborn and typically depends on results of serologic D typing. Interpretation and follow‐up of weak D serology is variable. Recent recommendations promote genotyping for RHD status determination in those with weak D serology. Canadian Blood Services performs comprehensive serologic prenatal testing in four provinces. Genotyping is used to determine D typing in patients with weak D. STUDY DESIGN AND METHODS A serologic algorithm identified which patients require genotyping for RHD determination. Genotyping was performed on one of two commercially available platforms. RESULTS Only 0.4% of D– patients met criteria for genotyping. Sixty‐one percent were weak D Type 1, 2, or 3. Thirty percent had a partial or weak D other than Type 1, 2, or 3. Eleven had variants which remained unresolved. Seventeen were D+ and four were D–. CONCLUSIONS Genotyping of patients with weak D serology led to an identified genotype in most patients. RhIG administration was avoided in 66% who were weak D Type 1, 2, or 3 or were D+. The use of a serologic algorithm to select patients for RHD genotyping identifies a majority of patients with weak D types not at risk for alloimmunization. This approach limits the number of genotyping investigations and the cost of providing classification for weak D types.