can vitamin b12 injection cause fever When deficiency strikes early: A case of pernicious anemia with neurological features Discover the Life-Giving Power of

Older Adults : Aging can reduce the bodys ability to absorb B12 from food

The United Kingdom National Quality Assessment Scheme for Haematinic Assays warns against false B12 results and the risk of neurological damage: In the event of any discordance between clinical findings of B12 deficiency and a normal B12 laboratory result, then treatment should not be delayed

Procedures such as total gastrectomy, gastric bypass and Whipple procedure bypass or remove parts of the body involved in digestion and the absorption of vitamin B12

Personally I would be wary of any B12 where a vial is used multiple times due to risk of contamination

Cautions You should never give yourself and injection unless you are fully confident in your ability to do it safely