Background We aimed to compare HPA‐1 to HPA‐6 and HPA‐15 genotyping results obtained by a simple‐probe real‐time polymerase chain reaction (PCR) technique with the multiplex PCR technique. Methods Five hundred DNA samples from the Thai National Stem Cell Donor Registry (TSCDR) of the National Blood Centre, Thai Red Cross Society were included. Human platelet antigen (HPA) genotyping was performed by simple‐probe real‐time PCR and multiplex PCR techniques. Results HPA‐1, HPA‐2, HPA‐3, and HPA‐4 genotyping results obtained by both techniques were in agreement. The misinterpretation of HPA‐5, HPA‐6, and HPA‐15 genotypes was found in eight samples by simple‐probe real‐time PCR and HPA genotypes were confirmed by DNA sequencing. Two samples of HPA‐5 were misinterpreted as HPA‐5a5a instead of HPA‐5a5b due to an NM_002203.3:c.1594A>C mutation (rs199808499) near the HPA‐5 polymorphism (5′ side). Five samples of HPA‐6a6b were misinterpreted as HPA‐6b6b because of an NM_000212.2:c.1545G>A mutation (rs4634) adjacent to the HPA‐6 polymorphism (3′ side). Interestingly, one sample of HPA‐15a15b was misinterpreted as HPA‐15b15b due to an NM_133493.1:c.2118C>A mutation near the HPA‐15 polymorphism (3′ side). Conclusions HPA genotyping results by two PCR techniques were compared. Incorrect assignments were found due to genetic variations near each HPA single nucleotide polymorphism. Therefore, to avoid false assignation, the use of two genotyping techniques is recommended.

Background: Different polymerase chain reaction (PCR) techniques for human platelet antigens (HPA) genotyping have been implemented, in order to diagnose the clinical syndromes of patients with thrombocytopaenia and provide effective HPA‐matched platelet donors. Objectives: The aim of this study is to develop an in‐house multiplex PCR for HPA‐1 to ‐7 and ‐15 genotyping in the Thai population. Methods: One hundred DNA samples of known HPA genotyping by the PCR with sequence‐specific primers (PCR‐SSP), as previously described, were tested with the multiplex PCR. Additionally, 300 DNA samples of group O donors were tested for HPA‐1 to ‐7 and ‐15 genotyping using multiplex PCR. Results: The comparison of HPA‐1 to ‐7 and ‐15 genotype results between multiplex PCR and PCR‐SSP technique was in 100% concordance. Interestingly, HPA‐2b2b genotype was found in two samples; however, other low‐incidence genotypes such as HPA‐1b1b, HPA‐5b5b, HPA‐6b6b and HPA‐7b7b were not found in this study. Moreover, 30 samples were randomly tested twice for HPA genotyping using the multiplex PCR and demonstrated reproducible results. Conclusions: This study shows that the in‐house multiplex PCR is simple, cost‐effective and suitable for HPA genotyping for routine laboratories in other developing countries. Nevertheless, a large‐scale evaluation of this technique through multicentre analysis is suggested.