Another article by our friend and my hero, endocrinologist Bruce H. R. Wolffenbuttel:
casereports.bmj.com/content...
The gist seems to be that materials called Macro-B12 can confuse lab test results for serum B12.
This seems to be yet another reason why serum B12 test results can be misleading or erroneous.
I invite comments, especially if I am in some way mistaken.