Elevated B12 blood levels are to be expected when you take supplements. The "normal" ranges for vitamin levels were made based on "normal" people---those with no symptoms of low B12---and so reflect only those who DO NOT TAKE vitamins.

It was my understanding that labs in the US only calibrate the machines up to 2000. So your higher number is puzzling. We had a med tech post on NT in the past that 2000 was the highest result possible today. I suppose you could call the lab and ask for an explanation. There might be labs who calibrate differently.

Having a high level is good because the higher the serum concentration, the more will move thru the blood brain barrier into the spinal fluid and hence the brain, where it is needed.

You won't need to keep your dosing at a high level, forever. You can lower it as you recover from your head injury. The next time you have testing, stop taking any B12 for a week before. This will give a more realistic test result. There is no toxic level of B12 anywhere in the research. So don't worry about that.

High B12 levels when there are NO SUPPLEMENTS being taken, suggest to doctors, that there is a disease process going on with that patient. Kidney disease, liver disease, some cancers, some infections of the bowel. That is the only worry. The B12 itself is not toxic, only reflective of something else...for those not taking vitamins.

Your high level does reflect that you are absorbing the oral form nicely from your supplement. That is good news.