Clinical Significance of Indeterminate Antibody to Hepatitis C in Cancer Patients

Most patients with cancer are screened for hepatitis C virus (HCV) infection using an antibody to HCV (anti-HCV) test. However, the importance of an indeterminate anti-HCV result is unknown. We investigated the clinical significance of an indeterminate anti-HCV result in cancer patients. We conducted a retrospective cohort study of cancer patients screened for HCV infection using ARCHITECT Anti-HCV at our institution between October 2016 and July 2024. Patients were categorized based on their anti-HCV results as patients with indeterminate anti-HCV and undetectable HCV-RNA in the absence of HCV treatment, and patients with reactive anti-HCV and chronic infection. We compared the two groups using univariable analyses and multivariable logistic regression analysis. Of the 112,180 patients screened with anti-HCV, 114 (0.1%) had indeterminate results; 101 of them with confirmed cancer were further analysed. Anti-HCV testing was repeated in 24 (24%) patients; most (84%) had non-reactive (46%) or indeterminate (38%) results. Among the 101 patients with indeterminate anti-HCV, 98 (97%) did not have proven HCV infection, but 3 (3%) had HCV infection. Multivariable analysis showed that male sex (adjusted odds ratio [aOR] 2.22, 95% confidence interval [CI] 1.40-3.53, p < 0.001), age ≥ 60 years (aOR 1.61, 95% CI 1.01-2.56, p = 0.046), hepatitis B or HIV coinfection (aOR 3.13, 95% CI 1.21-8.11, p = 0.019) and cirrhosis (aOR 6.67, 95% CI 2.05-21.69, p = 0.002) were more likely to have chronic than an indeterminate anti-HCV result. Indeterminate anti-HCV results are uncommon in cancer patients and rarely indicate HCV infection.