Magnesium doesn't show much. But you can do it anyway.
Only really low or really high mean much...with a broad "normal" in between.
That broad "normal" could still reflect you need some.

Definitely do the RA and Sed Rate. When was the last B12 you had? if ever? I've had two negative RA and Always elevated Sed Rate of around 25... always. I've also been always neg on ANAs.

Definitely do the others. Perhaps Glenn could give additional advice. I am not an expert on labs.

I would do the IgG, IgA and IgM. If IgM is elevated that would be of interest.

When did you have testing before? If you are taking B12 now it will reflect that.