Variable reactivity of Rh D antigen and its serological characterization

• Published in: Acta clinica belgica (English ed. Online) Vol. 76; no. 5; pp. 346 - 350
• Main Authors: S, Sreelekshmi, Shastry, Shamee, B, Poornima Baliga
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 03-09-2021; Taylor & Francis Ltd
• Subjects: Antigens; Blood group; partial D; Rh D; Serology; weak D; weak D; Blood group; Rh D; partial D
• ISSN: 1784-3286; 2295-3337
• DOI: 10.1080/17843286.2020.1735115

Background: Variation in the reactivity on Rh D typing may pose challenges in interpretation and ambiguity in further patient management.
Materials and Methods: A prospective study was conducted in the department of transfusion medicine for a period of 18 months. Blood grouping was performed by fully automated equipment employing column agglutination technique. All the samples with Rh D negative or discrepant reactions were subjected to weak D testing by the antihuman globulin testing method. Samples that tested positive were categorized as serological weak D type or Variant D and were further phenotyped with Partial D typing set with 6 monoclonal anti D antisera.
Results: A total of 82,824 samples were tested for Rh D type during the study period. Of the study population, 65.7% were males. On Rh D type majority were Rh D positive (93%), 6.9% were negative, and the result was discrepant in 0.1% (70) samples. The overall prevalence of variant D was 1.28% (75) of the Rh D negative population and 0.09% of the total study population. The detection rate of variant D phenotype was significantly higher by the Column agglutination technique. Upon testing with Partial D kit, the partial D variant in the majority reacted wil all the 6 antisera and hence we could not rule out DIII(60%), in rest it was inconclusive. In 43% of subjects with Rh D discrepancy 'C' antigen was found in a homozygous state.
Conclusion: The introduction of partial D typing kit alone may not help in the absolute characterization of variant D. Extended serological testing and selective integration of molecular testing is the need of the hour.