Table 5.

Adaptation (with permission) of Table 1. Summary of recommendations on testing for chronic hepatitis B and C virus infection, from WHO Guidelines on hepatitis B and C testing [10]). How to test for chronic HCV infection and monitor treatment response

HOW TO TEST FOR CHRONIC HCV INFECTION AND MONITOR TREATMENT RESPONSE
Topic	Recommendationsa
Which serological assays to use	• To test for serological evidence of past or present infection in adults, adolescents and children (>18 months of ageb), an HCV serological assay (antibody or antibody/antigen) using either RDT or laboratory-based immunoassay formatsc that meet minimum safety, quality and performance standardsd (with regard to both analytical and clinical sensitivity and specificity) is recommended. - In settings where there is limited access to laboratory infrastructure and testing, and/or in populations where access to rapid testing would facilitate linkage to care and treatment, RDTs are recommended. Strong recommendation, low/moderate quality of evidence
Serological testing strategies	In adults and children older than 18 monthsb, a single serological assay for initial detection of serological evidence of past or present infection is recommended prior to supplementary nucleic acid testing (NAT) for evidence of viraemic infection. Conditional recommendation, low quality of evidence
Detection of viraemic infection	• Directly following a reactive HCV antibody serological test result, the use of quantitative or qualitative NAT for detection of HCV RNA is recommended as the preferred strategy to diagnose viraemic infection. Strong recommendation, moderate/low quality of evidence • An assay to detect HCV core (p22) antigen, which has comparable clinical sensitivity to NAT, is an alternative to NAT to diagnose viraemic infectione. Conditional recommendation, moderate quality of evidence
Assessment of HCV treatment response	• Nucleic acid testing for qualitative or quantitative detection of HCV RNA should be used as test of cure at 12 or 24 weeks (i.e. sustained virological response (SVR12 or SVR24)) after completion of antiviral treatment. Conditional recommendation, moderate/low quality of evidence

Abbreviations: DBS dried blood spot, IVD in vitro diagnostics, NAT nucleic acid test, RDT rapid diagnostic test

^aThe GRADE system (Grading of Recommendations, Assessment, Development and Evaluation) was used to categorize the strength of recommendations as strong or conditional (based on consideration of the quality of evidence, balance of benefits and harms, acceptability, resource use and programmatic feasibility) and the quality of evidence as high, moderate, low or very low

^bHCV infection can be confirmed in children under 18 months only by virological assays to detect HCV RNA, because transplacental maternal antibodies remain in the child’s bloodstream up until 18 months of age, making test results from serology assays ambiguous

^cLaboratory-based immunoassays include enzyme immunoassay (EIA), chemoluminescence immunoassay (CLIA), and electrochemoluminescence assay (ECL)

^dAssays should meet minimum acceptance criteria of either WHO prequalification of IVDs or a stringent regulatory review for IVDs. All IVDs should be used in accordance with manufacturers’ instructions, and where possible at testing sites enrolled in a national or international external quality assessment scheme

^eA lower level of analytical sensitivity can be considered, if an assay is able to improve access (i.e. an assay that can be used at the point of care or suitable for dried blood spot [DBS] specimens) and/or affordability. An assay with a limit of detection of 3000 IU/mL or lower would be acceptable and would identify 95% of those with viraemic infection, based on available data