check vitamin b12 after injection What You Need to Know About Vitamin B12 Blood Test Laboratory

It is an important component of the body system because it is required for proper digestion, absorption and synthesis of foods, protein synthesis, and the metabolism of carbohydrates and fats

It doesn't require anything more exotic than the basic fact that this population is routinely left out of the research that would answer the question

Durai R, Yang SY, Seifalian AM, Goldspink G, Winslet MC

doi: 10.1097/MAJ.0b013e318063c6e4

This means that the term pernicious anaemia does by no means capture the full spectrum of B12 deficiency

The sublingual form is worth paying attention to because it absorbs directly into your bloodstream without going through your gut first