Table 4 Key challenges in assessing evidence on diagnostic tests to develop recommendations on testing for HBV or HCV infection

• Need to rely on intermediate outcomes (diagnostic accuracy), requiring inferences regarding effects on clinical/patient outcomes

• Methodological limitations in diagnostic accuracy studies

• Inconsistency in diagnostic accuracy estimates, with lack of reliable methods for measuring statistical heterogeneity

• Imprecision in some diagnostic accuracy estimates

• Difficulty in determining accuracy of some standard assays due to the absence of an alternative reference standard

• No standardized/validated criteria for clinically important differences in diagnostic accuracy

• Wide variety of commercially available HBV and HCV test assays with variable testing and regulatory oversight

• How to incorporate/weigh findings from predictive modeling studies

• How to weigh trade-offs between lower diagnostic accuracy and lower costs, increasing testing access, uptake, and linkage to care; greater feasibility; and/or values and preferences