Trying to figure out reason for high B12

Hi, recently I had some blood tests done and they’ve shown my B12 levels to be at 1406 pmol /L. I consulted my GP about this and he also found a blood test result of mine from 10 years ago showing B12 levels of 4500 pmol / L. Currently the only medication I am on is seroquel 100mg and Effexor 150mg. I have never taken any multivitamins or B12 supplements.

According to my GP my blood cultures look normal and my liver seems ok from the blood tests as well, also my sugar levels are normal so no signs of diabetes.

My GP was very confused and unsure of who to refer me to or what the problem may be.

In the end he has referred me to a liver specialist due to the 12 month + wait to see a hematologist

If anyone could provide some insight into this that would be much appreciated.