Improved allele-specific PCR technique for Kidd blood group genotyping.

BACKGROUND: We developed an allele-specific polymerase chain reaction (AS-PCR) technique for Kidd blood group genotyping. METHODS: Altogether, 340 blood samples from Thai blood donors at the National Blood Centre, Thai Red Cross Society, were tested with anti-Jk(a) and anti-Jk(b) using the gel technique and the direct urea lysis test was used for screening Jk(a-b-) phenotype. For AS-PCR technique, different types of primers were used for JK*01 and JK*02 allele detections in known DNA controls. RESULTS: Regarding JK*02 allele detection, the pseudopositve amplification products were found when using correctly matched forward primer and a single mismatch forward primer. Interestingly, one type of two mismatch pairing at the 3' end of the forward primer can be used together with the newly designed reverse primer for Kidd blood group genotyping. It was found that the typing results in all samples obtained by serological techniques and newly developed AS-PCR technique were in agreement and this PCR technique also gave 100% concordance of results in 30 samples randomly tested twice and demonstrated reproducible results. CONCLUSION: This study shows that the in-house AS-PCR is simple, cost-effective, and convenient for Kidd blood group genotyping in routine laboratories, especially, in resolving serologic investigations.

Clinical investigation of posttransfusion Kidd blood group typing using a rapid normalized quantitative polymerase chain reaction.

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. STUDY DESIGN AND 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. CONCLUSION: 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.