Vitamin B12 (serum)

Clinical Chemistry

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Description

Often measured with folate to assess nutritional status. B12 deficiency should be distinguished from folate deficiency in macrocytic anaemia. The neurological effects of B12 deficiency can be made worse if only folate is replaced. Vitamin B12 is obtained from animal products including milk and fish. Fruit and vegetables contain negligible amounts. Daily intake is normally in excess of requirements so dietary deficiency is rare except in strict vegetarians and vegans. Intrinsic factor is required for absorption. Lack of intrinsic factor ( e.g. pernicious anaemia, gastrectomy ) or intestinal malabsorption ( e.g. small intestine disease, ileal resection ) can therefore lead to B12 deficiency. Please also see Sheffield guidance on investigation of Vitamin B12 deficiency in adults on the GP CCG portal.

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Indications

Investigation of macrocytic, megaloblastic anaemia. Peripheral neuropathy with or without anaemia.

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Sample Type

Serum, SST/Gel, minimum 2 mL ( separated 1mL )

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Reference Range

Reference ranges are provided on the report. Alternatively, please contact the laboratory for current ranges.

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Turnaround Time

Within 2 days

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Testing Frequency

Daily

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Please note: the above information is subject to change and we endeavour to keep this website up to date wherever necessary.