b12 injection side effects period Vitamin and Safety What is the safety of

An inability to digest B12 as a result of low levels of intrinsic factor for either genetic reasons or a result of physical damage to the stomach or small intestine can also cause deficiency

A few require genetic testing to confirm hereditary intrinsic factor deficiency before approving injectable therapy, despite pernicious anemia predominantly being an acquired autoimmune condition

While there are a number of possible causal factors that may play a role, in the vast majority of cases no single specific cause can be identified

Some payers allow reporting of drug wastage using modifier JW (drug amount discarded)