External quality assessment of patient HLA-B*57:01 testing prior to abacavir prescription.
Hypersensitivity reactions to the drug abacavir are strongly associated with possession of HLA-B*57:01. Hence, patients with HIV/AIDS who may be prescribed abacavir should be tested for this HLA allele and the drug withheld from those that possess B*57:01. The UK National External Quality Assessment Service for Histocompatibility and Immunogenetics has operated a scheme for B*57:01 testing since 2008 which, in 2013, involved 47 participants from 12 countries. A total of 24 B*57:01-positive, 2 B*57:03-positive and 22 B*57-negative blood samples (including 2 B*58 samples) were distributed to between 28 and 47 laboratories each year over 6 years. Participants, who were unaware of the samples' HLA types, tested and reported on their B*57/B*57:01 status. A total of 1868 reports were assessed over the 6 years. Of the 880 reports on B*57:01 samples, 93.4% were correctly assigned as B*57:01, 2.8% were assigned as groups of B*57 alleles including B*57:01, and 3.3% were reported as B*57 positive only. Over the 6 years, there were four (0.46%) false B*57:01 negative reports. All the B*57:03-positive and B*57-negative samples, involving 72 and 916 assignments, respectively, were essentially reported as B*57:01 negative. Thus, there were no false B57:01 positive assignments. The reporting of B*57:01 status over the last 3 years of the scheme was 99.8% sensitive and 100% specific. Over the last year, it was 100% sensitive and 100% specific.
Welsh Transplantation and Immunogenetics Laboratory, Welsh Blood Service, United Kingdom National External Quality Assessment Service for Histocompatibility and Immunogenetics, Pontyclun, UK.
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Darke
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Corbin
D000483:Alleles; D019380:Anti-HIV Agents / Q000276:immunology / Q000627:therapeutic use; D015224:Dideoxynucleosides / Q000276:immunology* / Q000627:therapeutic use; D004342:Drug Hypersensitivity / Q000175:diagnosis / Q000235:genetics / Q000276:immunology*; D005820:Genetic Testing / Q000379:methods / Q000592:standards / Q000706:statistics & numerical data; D015235:HLA-B Antigens / Q000235:genetics / Q000276:immunology*; D006650:Histocompatibility Testing / Q000379:methods / Q000592:standards / Q000706:statistics & numerical data*; D006801:Humans; D016133:Polymerase Chain Reaction; D011786:Quality Control; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D000099227:Abacavir
D019380:Anti-HIV Agents; D015224:Dideoxynucleosides; D015235:HLA-B Antigens; D000099227:Abacavir; C484830:HLA-B*57:01 antigen