title: Clinical investigation of posttransfusion Kidd blood group typing using a rapid normalized quantitative polymerase chain reaction.
abstract: BACKGROUND
  Accurate typing of a patient's RBCs in the setting of prior transfusion or a hemolytic transfusion reaction is crucial in the selection of compatible blood but is time consuming, technically difficult, and sometimes impossible. To address this problem, a simple, rapid, and inexpensive quantitative PCR method was developed to identify the single nucleotide polymorphism (SNP) of the Kidd blood group. We applied this method in a clinical investigation of 54 multiple-transfusion patients.
  
  
  METHODS
  Patients were eligible if they had received at least one RBC transfusion within 30 days and had a sample referred to our regional reference lab for assistance with compatibility testing requiring reticulocyte separation, hypotonic saline treatment, or chemical modification to remove IgG. We compared serologic result to the normalized quantitative PCR. For discrepants, or where no serologic type could be assigned, DNA sequencing characterized the patient's Kidd SNP.
  
  
  RESULTS
  Of the 54 patients, the reference lab could assign a serologic Kidd type for 33. Quantitative PCR assigned a Kidd type for 53 of the 54. In three cases, where serology and PCR were discrepant, and for all cases where serology could not assign a Kidd type, DNA sequencing verified the Kidd typing assigned by PCR.
  
  
  CONCLUSIONS
  A simple, rapid, and accurate technique has been developed. The assay performs well in the clinical setting. With further study, and inclusion of other blood group systems, this may become an important supplemental technique for selected patients in the immunohematology reference laboratory.
authors.affiliation: Blood Systems Research Institute, Blood Centers of the Pacific, San Francisco, California 94118, USA.
authors.forename: Lani
authors.initials: L
authors.lastname: Montalvo
authors.forename: Phyllis
authors.initials: P
authors.lastname: Walker
authors.forename: Li
authors.initials: L
authors.lastname: Wen
authors.forename: Wilfredo
authors.initials: W
authors.lastname: Lim
authors.forename: William
authors.initials: W
authors.lastname: Reed
authors.forename: Michael P
authors.initials: MP
authors.lastname: Busch
authors.forename: Tzong-Hae
authors.initials: TH
authors.lastname: Lee
mesh_terms: D002138:Calibration; D017707:Erythrocyte Transfusion; D005838:Genotype; D006801:Humans; D007667:Kidd Blood-Group System / Q000145:classification / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*
chemical_list: D007667:Kidd Blood-Group System