Hi @dougs, welcome to Mayo Connect. I’m happy that you saw this discussion and hopped on board. You, @rubyjag3 and several others in the forum have higher than the ‘stated normal’ ranges for Blood serum B-12 levels. As we age there are changes in our chemistry where we may not be absorbing as much Vitamin B 12 as needed for optimism health. Taken as a supplement, Vitamin B-12 has no toxic limits as whatever isn’t used by the body is simply flushed away. It enters the blood stream and shows up as a high serum level.
The question is, why is it so high in some people when they’re not taking supplements? Finding the cause isn’t always easy. When it’s high, it can also mean the vitamin isn’t being utilized in the body and people with high serum levels can actually be experiencing very low B-12 levels on an essential level.
Low B-12 can cause strange sensations, numbness, or tingling in the hands, legs, or feet
difficulty walking (staggering, balance problems)
anemia
a swollen, inflamed tongue
difficulty thinking and reasoning (cognitive difficulties), or memory loss
weakness
fatigue
vision changes
hair loss
mental problems like depression or behavioral changes

Doing some research today I found some sites worth reading. This one gives a description of tests used in determining how well the body is using V-B12 besides the regular V-B 12 serum test. The article gets the point across and helps give a pretty good understanding on what’s happening with a high V-B 12 level and what it can mean.

-https://www.restartmed.com/how-to-test-for-vitamin-b12-deficiency/

I’m not advocating this site but this particular integrative medicine article has some interesting information on the importance of pursuing the cause of extremely elevated B-12 when someone is not actively taking supplements. https://www.swintegrativemedicine.com/blog/causes-of-high-b12-without-supplementation

This can also be caused by underlying health issues such as liver, kidney or blood diseases. So it’s important to get to the root of the problem. It seems there is a lot of dismissal from doctors that this isn’t anything to be concerned about. But from simple research it looks as though there can be some definite concern for potential health issues.

Have either you or @rubyjag3 thought about a second opinion with an Integrative Medical Professional?