The genomic dna sample was sent to (b)(4) for bi-directional sequencing.Sequencing interrogated gypa gene exons 1 to 7 and the allele genotype gypa*m, gypa*n(68a) was identified.Although the variant gypa*c.68c>a has been previously described as the isbt null allele gypa*11 associated with gypa*m, dna cloning and new sequencing of gypa exon 2 confirmed this result.Since the serology data for n antigen of this sample is negative, the gypa*n(68a) allele is associated to no expression.Id core xt reported a predicted n+ phenotype, but gypa*n(68a) variant allele, not interrogated by id core xt, is associated with n- phenotype.This false positive result obtained by id core xt is considered a discrepant result and then a malfunction.This case report is covered by limitations number 1 and 10 of id core xt package insert.
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