Highly Sensitive HBsAg, Anti-HBc and Anti HBsAg Titres in Early Diagnosis of HBV Reactivation in Anti-HBc-Positive Onco-Haematological Patients

Novel Assays to Solve the Clinical and Scientific Challenges of Chronic Hepatitis B

Chronic infection with Hepatitis B is a common, incurable, and deadly infection. Despite inexpensive laboratory tests for diagnosis and management that have been established for decades, the worldwide rate of diagnosis is only ∼10%, and ∼5% of people are under treatment. Novel assays have been developed to improve linkage to care by providing more flexible approaches to determine a patient's health status. Other assays have been established to better investigate intrahepatic host-virus interactions to support clinical trials for cure research. This review outlines the clinical and scientific challenges still to be solved and the upcoming methods used to address them.

ARCHITECT HBsAg Next assay is positioned better to resolve and refine challenging weak reactive clinical samples

BACKGROUND

Ultrasensitive HBsAg assays are replacing the previous versions. Unlike the sensitivity, the specificity, and its positioning to resolve weak-reactives (WR) are not studied. We investigated the ability of ARCHITECT HBsAg-Next (HBsAg-Nx) assay to resolve WR and sought its clinical validation and correlation with confirmatory/reflex testing.

METHODS

Among 99,761 samples between Jan 2022 - 2023, 248 reactive samples in HBsAg-Qual-II were compared with HBsAg-Nx assay. Sufficient samples were further subjected to neutralization (n = 108) and reflex (anti-HBc total/anti-HBs antibody) testing.

RESULTS

Out of 248 initial reactive samples in HBsAg-Qual-II, 180 (72.58%) were repeat reactive, and 68 (27.42%) were negative, whereas in HBsAg-Nx, 89 (35.89%) were reactive and 159 (64.11%) were negative (p<0.0001). Comparing the results of two assays (Qual-II/Next), 57.67% (n = 143) were concordant (++/-) and 105 (42.33%) were discordant (p = 0.0025). Testing of HBsAg-Qual-II + & HBsAg-Nx - samples revealed that 85.71% (n = 90) were anti-HBc total negative and 98.08% (n = 51) were not neutralized as well as significant proportion (89%) had no clinical correlation. The proportion of samples neutralized was significantly different between ≤5 S/Co (26.59%) and >5 S/Co (71.42%) (p = 0.0002). All samples (n = 26) with enhanced reactivity in HBsAg-Nx were effectively neutralized, while samples with no increase in reactivity, 89% (n = 72) failed neutralization (p=<0.001).

CONCLUSIONS

HBsAg-Nx assay is positioned better to resolve and refine challenging WR samples than Qual-II which correlated well with confirmatory/reflex tests and clinical disease. This superior internal benchmarking significantly reduced the cost and quantum of retesting, confirmatory/reflex testing in the diagnosis of HBV infection.

Clinical Utility of Quantitative HBV Core Antibodies for Solving Diagnostic Dilemmas

The present-day management of hepatitis B virus (HBV) infection relies on constant and appropriate monitoring of viral activity, disease progression and treatment response. Traditional HBV infection biomarkers have many limitations in predicting clinical outcomes or therapy success. Quantitation of HBV core antibodies (qAnti-HBc) is a new non-invasive biomarker that can be used in solving multiple diagnostic problems. It was shown to correlate well with infection phases, level of hepatic inflammation and fibrosis, exacerbations during chronic infection and presence of occult infection. Further, the level of qAnti-HBc was recognised as predictive of spontaneous or therapy-induced HBeAg and HBsAg seroclearance, relapse after therapy discontinuation, re-infection after liver transplantation and viral reactivation upon immunosuppression. However, qAnti-HBc cannot be relied upon as a single diagnostic test to solve all dilemmas, and its diagnostic and prognostic power can be much improved when combined with other diagnostic biomarkers (HBV DNA, HBeAg, qHBsAg and anti-HBs antibodies). The availability of commercial qAnti-HBc diagnostic kits still needs to be improved. The comparison of results from different studies and definitions of universal cut-off values continue to be hindered because many methods are only semi-quantitative. The clinical utility of qAnti-HBc and the methods used for its measurement are the focus of this review.

Importance of quantitative HBsAg detection in whole course management of patients with chronic hepatitis B

HBsAg is the earliest known serum marker for hepatitis B virus (HBV). It plays an important role in the pathogenesis, diagnosis, and prevention of chronic hepatitis B (CHB). In the era of antiviral therapy, the concept of functional cure is put forward. HBsAg, as an old marker of HBV infection, has been found to have more and more new applications in the management of CHB patients. Positive HBsAg is taken as the indication of antiviral treatment in special CHB patients. The level of HBsAg is conducive to the selection of treatment regimens, and the dynamics of HBsAg is conducive to the adjustment of treatment scheme. HBsAg level and its kinetics can predict the therapeutic effect and disease outcome, and guide drug withdrawal. Further research is needed on the sensitivity of HBsAg, its impact on long-term outcomes, and its value in functional cure and complete cure.