What does high vitamin b12 mean?

Ingesting much B12.: No known adverse effect of too much vitamin B12 in blood. You may not need to take any b12.

Needs evaluation: B12 is not toxic so high B12 due to taking it is not bad. If someone has high B12 without taking it then it can be a sign of serious problems including liver ; kidney disease, myelproliferative disorders including leukemia ; polycythemia vera ; hypereosinophilic syndrome. High B12 does not cause these but caused by them. Further tests are needed to find the underlying cause: http://bit.Ly/1hvpcy7.