Implementation considerations Adaptation of reflex HCV RNA testing recommendations for different country contexts Countries should incorporate routine reflex HCV RNA testing into their national testing guidelines and testing infrastructure. The choice between laboratory-based reflex testing and clinic-based reflex testing with POC HCV RNA tests will depend on national testing policies, budgets, infrastructure and human resources, as well as the extent of reliance on centralized high-throughput laboratories, the available sample transport network and location of testing and treatment services. While a laboratory-based reflex testing strategy will be more appropriate in settings with large testing volumes supported by extensive sample transport networks, clinic-based reflex sample collection for HCV RNA testing may be the preferred testing algorithm for populations such as key populations (such as people who inject drugs and men who have sex with men) and migrants and refugees who receive health care in community-based settings or in primary care and may have limited access to full-range phlebotomy and laboratory services. Instead, clinic-based reflex testing with initial HCV antibody RDTs followed by reflex sample collection for HCV RNA testing of those testing antibody-positive and then use of clinic-based POC HCV RNA testing may maximize linkage to care for such populations. To meet the needs of different populations or regions in a country, a mix of clinic-based and laboratory-based reflex testing strategies may be optimal. Key steps to initiate laboratory-based reflex HCV RNA testing

• Train outpatient clinic phlebotomy and laboratory staff on new procedures for specimen collection and processing of HCV RNA NAT testing.
• Update electronic laboratory order forms for anti-HCV and RNA testing to list reflex-only testing options and develop laboratory guidance for HCV reflex testing.
• Design the laboratory process to preserve specimen integrity and limit risk of crosscontamination.
• Plan for additional costs as needed, that is, additional tubes, transport and storage, if collecting two tubes for anti-HCV and NAT/cAg testing.
• Combine laboratory-based reflex HCV RNA NAT testing with other strategies, for example, clinic-based reflex testing, to meet the needs of different populations.
• Evaluate HCV laboratory-based reflex testing programmes, providing feedback to providers and laboratory managers for quality improvement. Other operational considerations
• Training for phlebotomists will be required to sensitize new protocols: If the reflex testing protocol requires two separate specimen tubes and phlebotomists are used to only collecting one specimen tube for HCV testing, appropriate training and quality management assurance systems are needed to sensitize phlebotomists to collecting two tubes and using two tube labels.
• Electronic ordering system updates must be comprehensive to disable all non-reflex testing options. Electronic ordering systems are not necessary for reflex testing, but they can help streamline the transition to a new clinical process.
• Designing the clinical process to collect one versus two specimens may depend on the assessed risk of contamination in the laboratory. Laboratory managers should assess the risk of cross-contamination for available testing platforms and develop procedures to minimize this risk.