I have thyroid cancer. Why am I being asked to have a hepatitis B blood test?

[Horsefood]

My consultant has sent me this but I don't know why ?

To add, I'm waiting for RAI treatment

Maybe your other blood tests have come back with something indicative of Hep B infection.

Sorry to hear about your cancer. Certain infections can get reactivated with certain cancer treatments so they just need to check if you've got anything underlying so that they can guide your treatment without making anything worse. Good luck with the treatment.

Now that I know you are waiting for treatment it is more likely that the treatment affects liver function and you must have optimal liver function to start.