Rapid genotyping of human platelets can improve the diagnosis and treatment of neonatal alloimmune thrombocytopenia and minimize the risks of posttransfusion purpura and refractoriness to random donor platelet therapy. Advances in genotyping using microarray technology allow the same sample to be screened for multiple polymorphisms without the need for reference sera or large sample size. At the National Institute of Blood Transfusion in Paris, France, 200 samples were screened using polymerase chain reaction (PCR)-sequence-specific primer or PCR-restriction fragment length polymorphism and BioArray BeadChip™ platform to evaluate the accuracy and liability of human platelet antigen genotyping. The results of this analysis are presented along with methods to minimize the impact of genotypic errors resulting from rare silent mutations.