About 18 months ago after developing neurological symptoms and other symptoms (such as breathlessness) and being told that my serum B12 level was "in range" (224) by my GP, I started to supplement using daily 5000mcg Methylcobalamin tablets and later with a spray also, along with a good B complex with folate. My symptoms improved and all but disappeared, but I have noticed more recently that some have returned so have upped my dose.
I know that a standard blood test will show high levels of serum B12, but which if any of the following tests could I have without the results being skewed by supplementation? I think it's maybe time to push the GP for a course of injections ......
Intrinsic factor
Active B12
MMA
Homocysteine
Parietal cell antibodies
MTHFR gene (my late father had PA)
Thanks