Summary
The discrimination between active chronic hepatitis B (CHB) and the clinically quiescent infection (CIB) is not always easy, as a significant portion of patients falls in a “grey” zone. Hepatitis B core‐related antigen (HBcrAg) is a now quantifiable serological marker with potential applications in diagnosis and therapy monitoring. The aim of the present study was to evaluate the HBcrAg serum levels in HBeAg‐negative HBV infection, and its ability in identifying the clinical profile, in comparison with HBsAg serum levels. HBcrAg was retrospectively assessed on serum samples from a population of treatment‐naive HBeAg‐negative patients by ChemiLuminescent Enzyme Immunoassay (CLEIA). HBsAg and HBV‐DNA data were collected. Serological data were associated to clinical profile, defined in the subsequent follow‐up of at least 1 year. In the overall population of 160 HBeAg‐negative patients, HBcrAg results weakly correlated with qHBsAg levels (Spearman r = 0.471, P < 0.0001) and correlated closely with HBV‐DNA (Spearman r = 0.746, P < 0.0001). HBcrAg levels were significantly higher in 85 CHB patients relative to 75 CIB carriers. A value of 2.5 logU/mL produced the optimal cut‐off to identify CIB patients, with diagnostic accuracy comparable to HBsAg levels. In long‐term clinical evaluation, a single measurement of HBcrAg at the established cut‐off was optimally consistent with clinical outcome. Conversely, the HBsAg cut‐off performed well in the true quiescent phase and less in more difficult‐to‐categorize patients. In conclusion, single‐point use of HBcrAg serum levels provides an accurate identification of CIB and represents a useful tool for patient classification.