Unexplained hypercobalaminemia, particularly levels above 1,000 pg/mL, has been associated with liver disease, kidney dysfunction, myeloproliferative disorders, and certain solid cancers in multiple large-scale studies
not safety or efficacy guidance
They may arrange blood tests to evaluate: Inflammatory markers (ESR, CRP) to detect active inflammation Rheumatoid factor and anti-CCP antibodies if inflammatory arthritis is suspected Full blood count to assess haematological response to B12 treatment Thyroid function tests , as thyroid disorders commonly coexist with B12 deficiency Note that serum B12 levels are not typically measured to assess treatment adequacy once replacement therapy has begun, as they may not reliably reflect tissue stores
[DOI] [PMC free article] [PubMed] [Google Scholar] 17.Zimmermann R, Strauss JG, Haemmerle G, Schoiswohl G, Birner-Gruenberger R, Riederer M, et al