A combination of different diagnostic tools allows identification of inactive hepatitis B virus carriers at a single time point evaluation

Abstract

Background & aims: Serial evaluation of hepatitis B virus (HBV) DNA and aminotransferase values is required for identification of inactive HBV carriers (ICs). Recently, HBV surface antigen quantification (qHBsAg) and liver stiffness measurement (LSM) have been proposed as diagnostic tools in chronic HBV infection. The aim of this study was to evaluate the efficacy of HBV DNA quantification, qHBsAg and LSM in diagnosing ICs at a single time point.

Methods: Fifty-seven previously characterized ICs and 90 untreated HBsAg-/anti-HBe-positive patients [49 chronic hepatitis (CH), 41 cirrhosis] were enrolled. HBV DNA ≤2000 IU/mL, LSM ≤6.2 kPa and qHBsAg ≤1000 IU/mL were used as cut-offs to evaluate sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy (DA).

Results: Combined HBV DNA quantification and qHBsAg correctly identified 30/57 (52.6%) ICs showing 94% sensitivity, 96% specificity, 98% PPV, 87% NPV and 95% DA. HBV DNA coupled with LSM identified 40/57 (70.2%) ICs showing 97% sensitivity, 97% specificity, 98% PPV, 95% NPV and 97% DA. Combined LSM and qHBsAg identified 33/57 (57.9%) ICs showing 95% sensitivity, 78% specificity, 89% PPV, 89% NPV and 89% DA. The evaluation of the three parameters altogether allowed the identification of 23/57 (40.3%) ICs showing 100% specificity, 96% sensitivity, 100% PPV, 92% NPV and 97% DA. Similar results were obtained when either CH or cirrhotic patients were excluded from the analysis.

Conclusions: Combined evaluation of HBV DNA amount with LSM and/or qHBsAg is a highly reliable tool allowing the identification of a considerable number of HBV ICs at a single time point evaluation.

Keywords: HBV DNA; Diagnostic accuracy; FibroScan; Inactive HBsAg carriers; quantitative HBsAg.