Detection of hepatitis B virus surface antigen, IgM and IgG antibodies to hepatitis B virus core antigen in the clinical classification and epidemiological surveillance of HBV infection

Hepatitis B virus surface antigen (HBsAg), IgM and IgG antibodies to hepatitis B virus core antigen (anti-HBcIgM and anti-HBcIgG) comprise serological markers of hepatitis B virus (HBV) infection of great importance in the epidemiological surveillance of hepatitis B, since they have been routinely considered for classifying the acute and chronic clinical forms of HBV infection. This classification is established according to the expression and dynamics of these markers in the infected person's bloodstream, which serves as the basis for the differential diagnosis between the two clinical entities. However, in certain circumstances, both acute and chronic infection, the detection of these markers may not occur in the bloodstream, favoring the occurrence of atypical serological profiles of infection, and compromising the correct infection clinical classification. In addition, the complex and varied nature of hepatitis B serological profiles may compromise the health professional's ability to analyze the case and, thus, correctly classify the infection's clinical form. Since the expression of these markers in the bloodstream occurs dynamically, with consequent changes in the patient's serological profile as he progresses towards recovery or chronicity, the diagnosis of acute or chronic infection may also be compromised, if it is established based on the collection of a single sample and without knowing the patient's clinical history and their epidemiological antecedents. This manuscript addresses the sensitivity and specificity of HBsAg, anti-HBcIgM, and anti-HBcIgG serological markers detection in the clinical classification of HBV infection and in the epidemiological surveillance of hepatitis B. This review is covering the clinical and epidemiological interpretations of the markers in and of themselves, not in reference to any specific assays.