Clinical performance of a prefabricated immunofluorescence assay for nasopharyngeal cancer screening

Background: Epstein–Barr virus (EBV) IgA serology for viral capsid antigen(VCA) and early antigen (EA) aids early detection of nasopharyngeal cancer(NPC), resulting in improved survival. We evaluated the diagnostic perfor-mance of a prefabricated immunofluorescent assay (IFA) for NPC screening inhigh-risk individuals. Methods: Sera from 96 biopsy-proven patients with NPC diagnosed at the out-patient clinic and 96 healthy family members were tested for EBV-VCA IgAand EBV-EA IgA using the prefabricated IFA from EUROIMMUN (EI) andthe traditional immunofluorescence method. Results: The AUC of EI EBV-VCA IgA and EBV-EA IgA was 0.907 (95% confi-dence interval [CI]: 0.894–0.965) and 0.898 (95% CI: 0.848–0.947), respectively. Combined testing with the prefabricated assay at a threshold of VCA ?1:320 orEA ?1:10 showed 92.7% sensitivity and 81.2% specificity. Overall, the tradi-tional EBV-EA IgA assay demonstrated the best accuracy (sensitivity 91.7%and specificity 96.9%) at a threshold of ?1:5.