Chronic Hepatitis B Infection: This is the most likely diagnosis given the positive hepatitis core antibody (indicating past or present infection), positive hepatitis surface antigen (indicating active infection), and negative hepatitis B surface antibody (indicating lack of immunity).

Acute Hepatitis B Infection: Although less likely than chronic infection given the presence of core antibodies, which often indicate a more established infection, it's still a possibility, especially if the patient is in the early stages of infection where surface antigen has appeared but surface antibody has not yet developed.
Hepatitis B Virus (HBV) Reactivation: In individuals with previously resolved HBV infection, reactivation can occur, leading to a positive surface antigen. However, this typically would be accompanied by a positive surface antibody, making it less likely but still a consideration.

Hepatitis B and Delta Coinfection: This is a serious condition that can lead to more severe liver disease. The serology pattern could be similar, but specific testing for hepatitis delta virus (HDV) would be needed for diagnosis.
Hepatitis B Virus Mutation: Certain mutations in the HBV genome can lead to a lack of surface antibody production despite active infection, mimicking the described serology pattern.

Vaccine-Associated Hepatitis B Surface Antigen Positivity: In rare cases, individuals who have received the hepatitis B vaccine may test positive for surface antigen due to the vaccine itself, although this is extremely uncommon and typically transient.
False-Positive Results: Although rare, laboratory errors can lead to false-positive results for any of the hepatitis B serologies, which would need to be confirmed with repeat testing.