Sensitivity of second-generation enzyme immunoassay for detection of hepatitis C virus infection among oncology patients

BackgroundThe second-generation hepatitis C virus (HCV) enzyme immunoassay (EIA 2), an antibody-detection test, has high sensitivity and is one of the recommended screening tests for detecting HCV infection in the United States. However, its sensitivity among oncology patients is unknown.ObjectiveAssess the EIA 2 sensitivity among a group of oncology patients at a Nebraska clinic where an HCV outbreak occurred during 2000–2001 using nucleic acid testing (NAT) and recombinant immunoblot assay (RIBA) as the gold standards.Study designSerum specimens were collected from patients 16 months after transmission had stopped. We tested the specimens using EIA 2 (Abbott HCV EIA 2.0), a NAT assay based on transcription-mediated amplification (TMA) (Gen-Probe TMA assay) and RIBA (Chiron RIBA® HCV 3.0 SIA). HCV infection was defined as a positive RIBA or TMA test in an oncology patient. Alanine aminotransferase (ALT) levels were determined in EIA 2-negative/TMA-positive samples.ResultsA total of 264 samples were included in the study. We identified 92 HCV infections, 76 of which were Abbott EIA 2 positive. Abbott EIA 2 sensitivity was 83% (76/92), lower than that reported among healthy adults (90%) (p = 0.01) and poor sensitivity was associated with receipt of chemotherapy during the outbreak period (p = 0.02). Only 1 (6%) of the 16 EIA 2-negative cases had elevated ALT.ConclusionsIn this study, EIA 2 sensitivity among oncology patients was lower than that previously reported among immunocompetent persons. Impaired antibody production related to cancer and/or chemotherapy might explain the reduced sensitivity. These findings indicate that, when assessing HCV status in oncology patients, a NAT test should be routinely considered in addition to EIA.