Dependence of Anti-JkaDetection on Screening Cell Zygosity

The importance of using commercial reagent red cells that always include a homozygous Jk(a + b − ) cell to screen patients′ sera for unexpected antibodies was evaluated. Reagent antibody screening cells consisting of a set of two single donor red cells were used throughout the study. Of 169,791 serum samples tested for unexpected antibodies, sera from 26 patients were found to contain anti-Jka, either alone (17 patients) or in combination with other unexpected antibodies (9 patients). During the first 31 months of the study only 44% of the patients′ sera was screened with sets of red cells that included a Jk(a + b − ) cell: a new anti-Jka was detected for every 9,976 sera tested and for every 5,890 patients transfused a delayed hemolytic transfusion reaction associated with anti-Jka occurred. During the following 20 months, 100% of the patients′ sera was screened with sets of red cells that included a Jk(a + b − ) cell: a new anti-Jka was detected for every 4,377 sera tested (P<0.05) and only one transfusion reaction was associated with anti-Jka after transfusing 12,080 patients. These data suggest that the omission of Jk(a + b − ) red cells from the antibody screening test could result in the failure to detect anti-Jka antibodies, which could potentially result in an increased incidence of hemolytic transfusion reactions associated with anti-Jka. It is recommended that at least one screening cell used for routine antibody detection methods be homozygous Jk(a + b − ).