Professor Tawesak Tanwandee, Professor of Gastroenterology at Mahidol University’s Siriraj Hospital, sits down to discuss how the HCV dual assay helps to streamline diagnosis and reduce patient dropout. The HCV dual assay represents a significant shift from conventional screening by providing independent antigen and antibody results from a single test that delivers results in under 30 minutes. Traditionally, the diagnostic journey involves a multi-step process – initial screening followed by a recall for RNA testing – which often leads to a 50% patient dropout rate. By providing both results during the same visit, the HCV dual assay reduces the need for repeated call-backs, potentially reducing loss-to-follow-up and reducing the necessity for RNA testing.
Prof Tanwandee also highlights that since the presence of the antigen is a surrogate marker for active viral replication, a positive antigen result has a 100% positive predictive value, allowing clinicians to link up to two-thirds of chronic hepatitis C patients directly to treatment, as supported by the World Health Organisation and European Association for the Study of the Liver guidelines.
Beyond standard chronic cases, the HCV dual assay offers critical advantages in early detection and specialised care. It can identify acute infections during the window period – roughly three weeks earlier than traditional antibody tests – which is vital for preventing further transmission. HCV antigen detection in the dual assay is particularly beneficial for immunosuppressed patients or those on haemodialysis who may have low antibody production, as well as high-risk groups like PWIDs (people who inject drugs) or MSM (men who have sex with men). For these populations, who may remain antibody-positive for life after an initial infection, the HCV dual assay is a powerful tool for detecting re-infections via antigen presence.
Ultimately, Prof Tanwandee emphasises that this technology optimises screening strategies by ensuring earlier intervention and better epidemiological outcomes across both general and high-risk populations.
