@kekimmel great advice. You can rest comfortably because supplementation was done AFTER testing. It also continues to be supervised and periodically retested. The D, the B12, now the iron. I have metabolic labs once a year through Medicare, I have labs done every other year before surgery and after, and I have some labs every 3 - 6 months depending on the issues. It is great because I have terrific trend lines. That was how my gout was finally diagnosed as well. My insulin resistance and many more things. Its amazing if I live a day without a doctoring experience these days!
IF my B12 is not necessary I will get insomnia. But the problem has now become that I think its a problem with my iron levels. So I am bringing those up and I am not going to do the B12. I don't do it just because it is scheduled. I have some great vitamins (Vitamin Code for women) those have tremendous B's so between injections, I'll take a supplement to see if I feel better. If I feel a lot better then I will inject.
However, there is even more to this - if your B12 isn't DIGESTING it can falsely run and be picked up in your blood serum and be a misguided test result.
So, for most people who are OLDER their body does a terrible job of digesting what they put in it. So they can try what I suggested without any danger if they are not already supplementing and IF it resolves their neuropathy, there isn't much chance their B12 was "already" too high.