What should I do if an adult patient needs screening for hepatitis B, but recently received the first dose of HepB vaccine elsewhere?

In general, this is not an issue, but CDC recommends waiting at least 1 month (4 weeks) after HepB vaccination before drawing blood for the triple panel screen for hepatitis B. HBsAg present in the HepB vaccine has been detected in serologic tests up to 18 days after vaccine administration. You do not have to delay the triple panel screen until after the vaccine series is complete, as long as it’s been at least 4 weeks since the most recent dose.

If you screen the patient after a partial HepB vaccination series, the screening results might show a positive anti-HBs antibody; however, you will still need to complete the vaccine series to ensure the patient develops long-term protection from infection.