Hypervitaminosis B12 is discussed far less frequently than vitamin B12 deficiency, despite being more common as well as clinically significant, remaining underdiagnosed and underestimated in routine practise. Its origin may arise from a broad spectrum of causes, ranging from benign excessive supplementation to serving as a marker of underlying pathology, including solid tumours, hematologic malignancies and hepatic or renal dysfunction. Despite these potential implications, most health centres lack standardized protocols for assessment and management of hypervitaminosis B12.A 40-year-old female presented elevated levels of vitamin B12 (1299 pg/mL) in a routinary laboratory evaluation with her primary care physician. The patient reported no accompanying symptoms, including fatigue, neuropathic manifestations or cognitive changes. No significant past medical history was reported, including malignancy, toxic substances or alcohol consumption, smoking history, known liver/kidney disease or autoimmune disease. No supplements intake was reported. Known allergies: pyrazolones. Medication: atorvastatin, paracetamol. IUD wearer. Physical examination revealed no clinically significant findings. Laboratory studies revealed persistently elevated serum vitamin B12 (1407 pg/mL) when re-tested 8 weeks later. The diagnostic work-up revealed no abnormalities in the other laboratory parameters, with the complete blood count within normal limits, normal liver enzyme levels and preserved renal function. A recent CT scan a couple months prior showed no significant alterations, only a non-obstructive 3mm lithiasis in the right kidney was observed. Once all probable secondary causes were ruled out, the hypervitaminosis B12 was considered idiopathic. Further laboratory assessments can be carried out to monitor these persistently elevated B12 values.Hypervitaminosis B12 is discussed far less frequently than vitamin B12 deficiency, despite being clinically significant, and remaining underdiagnosed and underestimated in routine practise.Primary care physicians are often the first to encounter abnormal vitamin B12 results. Recognizing elevated B12 levels as a potential marker of serious underlying pathology is essential.Persistently high levels of B12 warrant a comprehensive workup to rule out analytical interference and identify potentially occult diseases, particularly malignancies or organ dysfunction. A thorough evaluation can facilitate earlier detection and management, thereby improving patient outcomes.Primary care providers play a pivotal role in the early recognition and evaluation of hypervitaminosis B12.