COMPARISON OF FY(B) STATUS AS DETERMINED SEROLOGICALLY AND GENETICALLY

Comparison of the serologically determined phenotype and the genotype of samples as defined by PCR-RFLP indicated a significant percentage o f discrepancies on analysis of serologically defined Fy(a + b-) sample s. An investigation of these discrepancies has shown that the serologi cally determined phenotype of the samples varies with respect to the r eagent used but that the PCR-RFLP assay gives reliable results for all the samples investigated. The samples which yielded the discrepant re sults were further investigated and the results indicated weakened exp ression of the Fy(b) antigen. This may arise by a method similar to th e expression of Fy(x) although we found the incidence of these samples to be much higher than that reported for Fy(x). These results may hav e important implications for the routine testing of blood donations, p articularly in situations where the unit is to be transfused to a pati ent who has previously formed an anti-Fy(b).