Table 4. Interpretation of serologic test results* for HBV infection
|HBsAg†||Total anti-HBc§||IgM¶ anti-HBc||Anti-HBs**|
|+††||-||-||-||Early acute infection; transient (up to 18 days) after vaccination|
|-||+||+||-||Acute resolving infection|
|-||+||-||+||Recovered from past infection and immune|
|-||+||-||-||False positive (i.e., susceptible); past infection; “low-level” chronic infection§§; passive transfer to infant born to HBsAg-positive mother|
|-||-||-||+||Immune if concentration is >10 mIU/mL,¶¶ passive transfer after HBIG administration|
* Symbol for negative test result, “–“; symbol for positive test result, “+”.
† Hepatitis B surface antigen.
§ Antibody to hepatitis B core antigen.
¶ Immunoglobulin M.
** Antibody to HBsAg.
†† To ensure that an HBsAg-positive test result is not a false positive, samples with repeatedly reactive HBsAg results should be tested with an FDA-cleared (and, if appropriate, neutralizing confirmatory) test.
§§ Persons positive for only anti-HBc are unlikely to be infectious except under unusual circumstances involving direct percutaneous exposure to large quantities of blood (e.g., blood transfusion and organ transplantation).
¶¶ Milli-International Units per milliliter.