Importance of Hepatitis C Virus RNA Testing in Patients with Suspected Drug-Induced Liver Injury

Background and Aims: The aims were to review the diagnosis, testing and presentation of acute hepatitis C (HCV) in patients initially diagnosed to have drug-induced liver injury (DILI) enrolled in the US DILI Network. Methods: All patients with suspected DILI underwent testing for competing causes of liver injury and returned for 6-month follow-up. Causality was adjudicated by consensus expert opinion. Results: Between 2004 and 2016, 1518 patients were enrolled and adjudicated and underwent 6 months of follow-up. Initial locally acquired anti-HCV results were available in 1457 (96%), but HCV RNA in only 795 (52%). Stored sera were available for repeat testing, so that results were available on all 1518 patients (1457 for anti-HCV and 1482 for HCV RNA). A total of 104 subjects (6.9%) had evidence of HCV infection—10 positive for HCV RNA alone, 16 for anti-HCV alone and 78 for both. All 104 HCV-positive cases were reviewed, and 23 cases were adjudicated as acute HCV. All presented with acute hepatocellular injury with median ALT 1448 U/L, alkaline phosphatase 232 U/L and total bilirubin 10.8 mg/dL. Twenty-two (96%) patients were jaundiced. While all 23 cases initially had been suspected of having DILI, 19 were adjudicated as acute HCV and not DILI at the 6-month follow-up; while 4 were still considered DILI. Conclusions: Twenty-three of 1518 (1.5%) cases of suspected DILI were due to acute HCV infection. We recommend that initial and follow-up HCV RNA testing should be performed to exclude HCV in patients with acute hepatocellular injury and suspected DILI.