What test(s) should be ordered?
The USPSTF recommends screening using HBsAg. The CDC recommends using triple-panel screening: HBsAg, anti-hepatitis B surface antigen (anti-HBs), and total antibody to hepatitis B core antigen (anti-HBc).
HBsAg indicates HBV infection, either acute or chronic, or a recent dose of HBV vaccine. Anti-HBs indicate recovery from HBV infection, response to HBV vaccine, or recent receipt of hepatitis B immune globulin. Total anti-HBc develops in all HBV infections, resolved or current, and usually persists for life. Vaccine-induced immunity does not cause anti-HBc to develop.
The USPSTF’s rationale is that testing for HBsAg is more than 98% sensitive and specific for detecting HBV infections.2 The CDC recommends triple testing because it can detect those with asymptomatic active HBV infections (this would be a rare occurrence); those who have resolved infection and might be susceptible to reactivation (eg, those who are immunosuppressed); and those who are susceptible and need vaccination.
Interpretation of HBV test results and suggested actions are described in TABLE 2.1,8,13
Why do the CDC and USPSTF differ?
While it would be optimal if the CDC and the USPSTF coordinated and harmonized recommendations, this is difficult to achieve given their different missions. The USPSTF is charged to make evidence-based recommendations about preventive services such as screenings, behavioral counseling, and preventive medications, which are provided by clinicians to individual patients. The Task Force uses a very strict evidence-based process and will not make recommendations unless there is adequate evidence of efficacy and safety. Members of the Task Force are primary care professionals, and their collaborating professional organizations are primary care focused.
The CDC takes a community-wide, public health perspective. The professionals that work there are not always clinicians. They strive to prevent as much illness as possible, using public health measures and making recommendations to clinicians. They collaborate with professional organizations; on topics such as hepatitis and other infectious diseases, they collaborate with specialty-oriented societies. Given the imperative to act with the best evidence available, their evidence assessment process is not as strict.
The result, at times, is slight differences in recommendations. However, the HBV screening recommendations from the CDC and the USPSTF agree more than they do not. Based on practice-specific characteristics, family physicians should decide if they want to screen all adults or only those at increased risk, and whether to use single- or triple-test screening.