Planned and emergent implementation strategies during national scale-up of hepatitis C point-of-care testing in Australia: a retrospective case study

Background Scaling up point-of-care testing requires implementation strategies across policy, program, service, and community levels, yet how these strategies are configured, adapted, and sustained over time is rarely examined. The Australian Hepatitis C Point-of-Care Testing Program is one of the first programs globally to scale up molecular hepatitis C point-of-care testing; by July 2026, it supported 113 services nationally and had delivered 75,878 antibody and RNA tests. We examined the configuration and evolution of planned, adapted, and emergent implementation strategies across the program. Methods We conducted a retrospective case study using 28 program documents, records from 124 implementation meetings, and interviews with 30 stakeholders across six states and territories. Strategy instances were coded using the Expert Recommendations for Implementing Change (ERIC) taxonomy, consolidated into distinct implementation strategies, and classified by implementation domain, trajectory, delivery level, timing, and evidence provenance. We examined how strategies operated together and derived implications for scale-up planning. Results The analysis identified 328 strategy instances, consolidated into 79 distinct strategies across nine implementation domains. Twenty-four (30%) were prospectively planned and implemented substantially as planned, 15 (19%) were planned and adapted, and 40 (51%) emerged in response to implementation experience. Governance and stakeholder partnerships formed the largest domain (n = 23), whereas client and community engagement (5/6 emergent), support for testing operators (4/5), and adaptation of the testing model to context (5/9) were predominantly emergent. Thirty-nine strategies were jointly delivered by the central program and services, 31 were primarily central, and nine were service-delivered; all service-delivered strategies were emergent. Seventeen strategies were first introduced during national scale-up and none during ongoing delivery, although 66 remained active. Planned strategies were documented mainly prospectively, whereas emergent strategies were identified primarily through stakeholder interviews. Interpretive synthesis generated a three-layer model comprising a nationally specified backbone, adaptive implementation infrastructure, and locally configured service delivery. Conclusion The national scale-up of hepatitis C point-of-care testing combined a central implementation backbone with ongoing adaptation and local configuration across settings. Future scale-up plans should distinguish what must be specified in advance, what can be configured locally, and what capacity is needed for ongoing learning and adaptation.