selfadministered vitamin b12 injections Shots at Home: How, Where & How Often to Inject Yourself Vitamin B12 Deficiency - Needle
Description
These injections are typically administered subcutaneously, with a recommended dosage of 250 g per cat on a weekly basis until anemia resolves and red blood cell values stabilize

Vitamin B-12 is naturally found in meat, fish, and other high-protein foods
Available from: Li W, Zhao J, Zhu LL, Peng YF

What remains must independently support the E/M code

It's not always the case, but I would have expected something as well as an unmeasurable B12

I heard more than 2 clicks during my injection2 loud clicks and 1 soft one
