Trends in Reflexive Hepatitis C Virus Testing in a National US Laboratory: A Retrospective Study From 2018 to 2024

BACKGROUND: In 2019 and 2020, universal hepatitis C screening of adults was recommended by clinical guideline authorities, including the Centers for Disease Control and Prevention (CDC). In 2023, CDC recommendations emphasized the importance of reflexive hepatitis C testing in which samples positive for hepatitis C virus (HCV) antibody (Ab) automatically reflex to viral RNA nucleic acid amplification testing (NAAT). Laboratory stewardship initiatives to guide compliance with expanded guidelines were implemented. METHODS: We conducted a retrospective review of 38 233 788 specimens with HCV Ab testing and 1 423 543 follow-up HCV RNA NAAT performed from 2018 to 2024 to evaluate the impact of expanded hepatitis C guidelines and laboratory stewardship initiatives. RESULTS: From 2018 to 2024, reflexive hepatitis C testing volumes increased annually, while orders for standalone HCV Ab testing and HCV Ab positivity rates steadily declined. Among HCV Ab-positive individuals, the percentage with reflexive testing increased from 21.9% in 2018 to 82.2% in 2024 (Ƭ = 1.00, P = .003) and RNA testing rates increased from 66.4% in 2018 to 89.3% in 2024 (Ƭ = 1.00, P = .003). Follow-up RNA testing was increasingly completed earlier in HCV Ab-positive individuals with the same-day RNA testing rate increasing from 38.0% in 2018 to 82.2% in 2024. HCV RNA positivity decreased 19.2% during the study period. CONCLUSIONS: Expanded hepatitis C screening guidelines highlighting the importance of reflexive HCV testing and subsequent internal laboratory stewardship initiatives likely contributed to the increased utilization of reflexive hepatitis C testing and the decreased time to identification of active hepatitis C infection.