Proposed functional HBV categorisation of patients based on screening test results
| Screening test results | Risk of progression during biological therapy | Management considerations | |
|---|---|---|---|
| Never infected | HBcAb negative, HBsAg negative, HBsAb negative | None | Consider HBV vaccination if at risk of acquiring HBV |
| HBV vaccinated | HBcAb negative, HBsAg negative, HBsAb positive | None | N/A |
| Resolved HBV* | HBcAb positive, HBsAg negative, HBsAb positive | †Immunity suggested | Obtain baseline HBV DNA |
| Low risk (but not zero) | If positive: patient has chronic HBV | ||
| If negative: periodic monitoring of HBV-DNA levels and liver function tests during biological therapy | |||
| HBcAb positive, HBsAg negative, HBsAb negative | ‡Immunity not clear | ||
| Low to moderate risk of progression | |||
| Chronic HBV | HBsAg positive, (regardless of other results) | High | If biological therapy is not avoidable, then refer to GI or ID specialist for concurrent and appropriate anti-HBV therapy |
| Periodic monitoring of HBV-DNA levels and liver function tests during biological therapy |
* Patients in this category may also rarely be HBsAb positive in isolation.
† Patients with HBsAb positivity have probably cleared their virus, although there still exists a small risk of seroreversion and reactivation during immunosuppresssion.8
‡ In the case of HBsAb negativity, this substantially increases the risk that a patient has not cleared their HBV infection. Some proportion of these patients have either occult viraemia (detectable serum HBV DNA) or can reactivate later during immunosuppression in which HBV DNA and/or surface antigen will become detectable.
HBcAb, hepatitis B core antibody; HBsAb, hepatitis B surface antibody; HBsAg, hepatitis B surface antigen; HBV, hepatitis B virus.