Hepatitis B surface antibody
What this test measures
Anti-HBs is the antibody the immune system makes against the hepatitis B surface protein. It appears after vaccination or after clearing an infection, and shows protection.
Why doctors request it
Checked after hepatitis B vaccination, especially for healthcare workers, and as part of hepatitis screening.
What commonly pushes it up
- Successful vaccination
- Past infection that has cleared, usually with core antibody present too
What commonly pushes it down
- A level that fades years after vaccination
- Vaccination that did not take, which is common in some groups
Everyday reasons for a value outside the range
- Above 10 IU/L is the level usually taken as protective and above 100 as a strong response
- Levels fall over years even though protection often persists
About the sample
Best checked one to two months after the last vaccine dose.
Upload a photo or PDF and see every line against the range your lab printed, explained in plain English. First report free.
Read my report freeThis is an educational summary of results you uploaded. It is not medical advice, a diagnosis or a treatment plan, and it does not replace the doctor who requested the test. If you are worried, or a result is marked outside range, discuss it with your doctor. Written and reviewed by a UK consultant physician. Reference ranges vary between laboratories.