title: Rh discrepancies caused by variable reactivity of partial and weak D types with different serologic techniques.
abstract: BACKGROUND
  RhD discrepancies between current and historical results are problematic to resolve. The investigation of 10 discrepancies is reported here.
  
  
  METHODS
  Samples identified were those that reacted by automated gel technology and were negative with an FDA-approved reagent. Reactivity with a commercially available panel of monoclonal anti-D was performed. Genomic DNA was evaluated for RHD alleles with multiplex RHD exon polymerase chain reaction (PCR), weak D PCR-restriction fragment length polymorphism, and RHD exon 5 and 7 sequence analyses.
  
  
  RESULTS
  The monoclonal anti-D panel identified two samples as DVa, yet possessed the DAR allele. Two weak D Type 1 samples had a similar monoclonal anti-D profile, but only one reacted directly with one of two FDA-approved anti-D. Only two of four weak D Type 2 samples reacted directly with one FDA-approved anti-D, and their D epitope profile differed.
  
  
  CONCLUSIONS
  The monoclonal anti-D reagents did not distinguish between partial and weak D Types 1 and 2. Weak D Types 1 and 2 do not show consistent reactivity with FDA-approved reagents and technology. To limit anti-D alloimmunization, it is recommended that samples yielding an immediate-spin tube test cutoff score of not more than 5 (i.e., < or =1+ agglutination) or a score of not more than 8 (i.e., < or =2+ hemagglutination) by gel technology be considered D- for transfusion and Rh immune globulin prophylaxis. That tube test anti-D reagents react poorly with some Weak D Types 1 and 2 red cells is problematic, inasmuch as they should be considered D+ for transfusion and prenatal care. Molecular tests that distinguish common partial and Weak D types provide the solution to resolving D antigen discrepancies.
authors: Department of Pathology, Mount Sinai Hospital, USA. greg.denomme@blood.ca
authors: Gregory A
authors: GA
authors: Denomme
authors: Louann R
authors: LR
authors: Dake
authors: Daniel
authors: D
authors: Vilensky
authors: Lily
authors: L
authors: Ramyar
authors: W John
authors: WJ
authors: Judd
mesh_terms: D000483:Alleles; D000911:Antibodies, Monoclonal / Q000276:immunology; D005091:Exons / Q000235:genetics; D005838:Genotype; D006801:Humans; D007518:Isoantibodies / Q000276:immunology; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012204:Rh-Hr Blood-Group System / Q000235:genetics* / Q000276:immunology*; D018029:Rho(D) Immune Globulin
chemical_list: D000911:Antibodies, Monoclonal; D007518:Isoantibodies; C061961:RHO(D) antibody; D012204:Rh-Hr Blood-Group System; D018029:Rho(D) Immune Globulin; C026410:Rho(D) antigen