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Observational Study
. 2025 Sep;91(3):106601.
doi: 10.1016/j.jinf.2025.106601. Epub 2025 Aug 21.

Evaluation of Hepatitis B core-related antigen (HBcrAg) as a biomarker in cohorts from the United Kingdom and South Africa

Louise O Downs  1 , Marion Delphin  2 , Marije van Schalkwyk  3 , Susan Hugo  3 , Sheila F Lumley  1 , Elizabeth Waddilove  2 , Tingyan Wang  4 , Jacqueline Martin  5 , Catherine de Lara  4 , Arran Babbs  4 , Monique I Andersson  6 , Richard H Glashoff  7 , M Azim Ansari  4 , Kosh Agarwal  8 , Geoffrey Dusheiko  8 , Jantjie Taljaard  3 , Wolfgang Preiser  9 , Eleanor Barnes  10 , Gavin Kelly  2 , Ivana Carey  8 , Yusuke Shimakawa  11 , Tongai G Maponga  9 , Philippa C Matthews  12
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Free article
Observational Study

Evaluation of Hepatitis B core-related antigen (HBcrAg) as a biomarker in cohorts from the United Kingdom and South Africa

Louise O Downs et al. J Infect. 2025 Sep.
Free article

Abstract

Objectives: We set out to evaluate Hepatitis B core-related antigen (HBcrAg) as a proxy for hepatitis B (HBV) viral load (VL) and liver disease in two different population settings.

Methods: We undertook a cross-sectional retrospective observational study using samples and data from adults living with chronic HBV infection from the United Kingdom (UK, n=142) and South Africa (SA, n=211). We assessed HBcrAg distribution, relationship with other biomarkers, and risk stratification performance, applying point of care test (POCT) thresholds.

Results: SA and UK cohorts differed by ethnicity, HIV coinfection, HBeAg-positivity and proportion with HBV VL >200,000 IU/ml (all p<0.001). HBcrAg positively correlated with alanine aminotransferase (ALT) (in both settings p<0.01), and fibrosis/cirrhosis by APRI score (p=0.03 in UK, p=0.008 in SA), but not with elastography or FIB-4 scores. HBcrAg ≥4.3 log10U/ml (POCT threshold) was 100% sensitive and 92% specific for predicting VL >200,000 IU/ml in the UK cohort, compared to 94% sensitive and 86% specific in the SA population.

Conclusions: HBcrAg correlated with VL, but less so with liver disease. Use of this biomarker needs tailoring for use in diverse populations.

Keywords: Biomarker; Core related antigen; HBV; HBcrAg; Hepatitis B; Monitoring.

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Conflict of interest statement

Declaration of Competing Interest PCM and EB have previously received funding from GSK to support a PhD fellowship and the NIHR Health Informatics Collaborative for viral hepatitis, outside the scope of this paper. All authors declare that they have no other known competing financial interests or personal relationships that could have influenced the work reported in this paper..

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