Back on 10/1/25 I had someone’s blood get on me (no opens cuts and didn’t go in mouth, just on the unbroken skin).
Just to play it safe I went and had a test done on 10/3/25. At that time my Anti-HBs (along with stuff for HEP C and HIV) were non reactive.
I just went back in on 12/5/25 and was tested again. This time my anti-HBs showed <3.5 mIU/mL. HEP C and HIV still non-reactive.
I’m taking this means I have low levels of surface antibodies to HBV? I’ve never been vaccinated before (or at least don’t think I have/it’s been so long I don’t remember/not in my adult life) and plan on following up to have more in depth testing done.
I have non-alcoholic fatty liver disease and have had slightly elevated ALT/AST for the past several years.
Is there a potential that the reading for the anti-HBs is a false positive with the number so low? Or has anyone ever heard of these being a false positive? I would think the anti-HBs would be higher if I did have a recent infection that was gone already.
To follow what @ThomasTu said, there are qualitative (result is either positive or negative) and quantitative (gives you a numeric value) tests for surface antigen and antibodies. For the antibody test, a value >10 is considered positive, and less than 10 is considered negative. So it seems that you got the qualitative test the first time, and quantitative the next time. Neither of your results indicate immunity, so the best thing to do would be to get the vaccine.
It is correct that if you have been exposed and infected with Hepatitis B, there remains some DNA in the liver even after you clear it and/or you are negative for HBV DNA in the blood. However, in this case, there is no evidence that @HelpUnderstanding has been exposed to hepatitis B.