A Multi-Component Implementation Strategy to Expand Hepatitis B Screening in Primary Care in Viet Nam: A Mixed-Methods Study

Background. Chronic hepatitis B (CHB) remains substantially underdiagnosed in Viet Nam despite widespread availability of effective antiviral therapy. In routine primary care, hepatitis B surface antigen (HBsAg) testing is typically performed only when clinically indicated, resulting in missed opportunities for early detection. Evidence on how to operationalize routine hepatitis B screening in real-world, resource-constrained primary care settings is limited. Methods. We conducted a quasi-experimental implementation trial with mixed-method evaluation at a large public primary care hospital in Ho Chi Minh City, Viet Nam. A three-component strategy informed by constructs from the Consolidated Framework for Implementation Research (CFIR), including continuing medical education (CME), an electronic best practice advisory (BPA), and point-of-care (POC) HBsAg rapid testing, was introduced sequentially over 12 months. Implementation outcomes (adoption, reach) and service outcomes (weekly HBsAg testing per 1,000 visits) were evaluated using electronic medical record data, Kaplan–Meier and Cox regression analyses, and segmented negative binomial interrupted time-series models. Negative control outcomes (LDL and glucose testing) were analyzed in parallel. Qualitative data from observations and interviews were analyzed using a CFIR 2.0-guided framework to interpret mechanisms and contextual influences. Results. Among 225,209 outpatient visits and 46,857 unique patients, CME improved provider knowledge but resulted in only modest changes in testing. BPA reminders were frequently bypassed during high-volume sessions, limiting adoption. In contrast, introduction of free POC HBsAg rapid testing produced a sharp and sustained increase in weekly testing rates and substantially shortened time-to-testing among eligible patients. These effects were substantially larger than those observed for negative control outcomes, supporting a strategy-specific effect rather than background testing trends. Qualitative findings indicated that removal of financial and procedural barriers was central to uptake, while workflow constraints and team-based task division shaped implementation performance. Conclusions. A multi-component implementation strategy integrating provider education, EMR-based clinical decision support, and point-of-care HBsAg rapid testing substantially increased hepatitis B screening uptake in a high-volume public primary care system in Viet Nam. Structural interventions that remove financial and workflow barriers appear necessary for successful implementation. Integrating HBV screening into routine primary care workflows may represent a scalable strategy to accelerate hepatitis B diagnosis and support progress toward global elimination targets. Registration: NCT06403657 on ClinicalTrials.gov