Assumption and justification

People categorised as false negative for fibrosis would return and be re-diagnosed as true positive within 1 year

Prevalence rates for stages of fibrosis were different for VTq and TE based on the EAC’s meta-analyses. The combined hepatitis B and C prevalence rates for VTq were used for TE and liver biopsy in the model to ensure compatibility

Combined hepatitis B and C prevalence and diagnostic accuracy figures for F ≥ 3 fibrosis were not available from the meta-analysis. The EAC therefore used figures for hepatitis C across the model for this stage

Treatment delay resulting from misdiagnosis was unlikely to have a clinical impact and so long-term modelling of disease progression was not needed. According to published clinical evidence and expert advice gathered by the EAC, progression in both hepatitis B and C is relatively slow

People diagnosed as being at stage F ≥ 2 had fibrosis and those at stage F ≤ 1 did not

The majority of misclassified (false positive) cases for VTq and TE would be diagnosed as having F2 fibrosis. A proportion of those with F2 fibrosis would be misclassified as having F3 or F4 fibrosis. These proportions were chosen arbitrarily and subjected to sensitivity analyses

People diagnosed with F3 or F4 fibrosis would have antiviral therapy

A mortality risk of 0.003 would apply to liver biopsy

EAC External Assessment Centre, TE transient elastography, VTq Virtual Touch™ Quantification