The GP will take a detailed history including: Current medications and supplements (particularly B12 injections or high-dose oral preparations) Alcohol consumption and risk factors for liver disease Personal or family history of haematological disorders or cancer Symptoms suggesting underlying pathology Recommended investigations: Patients with unexplained elevated B12 should undergo: Repeat B12 measurement to confirm persistence, ideally timed away from recent injections or high-dose supplements Full blood count (FBC): To identify polycythaemia, leucocytosis, or other haematological abnormalities Liver function tests (LFTs): Including ALT, AST, ALP, bilirubin, and albumin to assess hepatic function Renal function tests: Urea, creatinine, and estimated glomerular filtration rate (eGFR) Lactate dehydrogenase (LDH): Elevated in haemolysis, liver disease, and some malignancies Further investigations may include: Abdominal ultrasound or CT scanning if liver disease or malignancy suspected Haematology referral for bone marrow examination if myeloproliferative disorder considered Liaison with the laboratory if results conflict with the clinical picture, as immunoassay interference (e.g., macro-B12) may occur In specialist settings, measurement of holo-transcobalamin or B12-binding proteins may be considered The urgency of investigation depends on clinical features and suspected underlying conditions
Other symptoms include fever, nausea, bloating, a change in bowel habits, and tenderness when pressing on the abdomen
Strategies that help include having a small amount of water before injection, waiting 15-20 minutes after injection before engaging in strenuous activity, and gradually adjusting to the morning fasting window if this is new to your routine
13 TECHNIQUE Pharmaceuticals and equipment are listed in Table 1
Always consult your doctor if you miss multiple doses
