b12 injection prescribing information Hydroxocobalamin: Package Insert / Veterinarians may prescribe vitamin B12 injections to animals with a deficiency B-12 Compliance Injection: Package Insert
Description
Medicare generally treats assays as screenings that include multiple vitamin assays and are therefore nondeductible

2016 Nov;42(5):31627

Here is who really needs them, at what frequency, and how we approach them at CoLaz

Adequate vitamin B12 levels support healthy nerve function and DNA synthesis, both of which are important for the development and activity of white blood cells