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Vitamin B12
(a.k.a B12)
minimum sample volume required ~ 5ml
Test Code: B12
Tube type: SST
Other acceptable tube types
Lithium heparin (pale green)
Special instructions
None
Reference Range
Please refer to thresholds and interpretative comments on individual reports.
<145 ng/L: deficiency
145-180 ng/L: possible deficiency
>180 ng/L: deficiency unlikely
>914 ng/L: raised serum vitamin B12
Time limit for add on
48 hours post collection.
Minimum retesting interval
Test should not be repeated within 42 days
Units
ng/L
Linked to
Haematinics
Turnaround Time
2
days
Department: Biochemistry
Clinical Application
NICE NG239 thresholds DO NOT apply to the local method.
Vitamin B12 is part of the B complex of vitamins and is found in animal products, e.g. red meat, fish, milk and eggs. It is essential for red cell formation, tissue repair, and DNA synthesis. Vitamin B12 deficiency can result in varying degrees of neuropathy. In severe deficiency a more serious nerve damage, known as subacute combined degeneration of the cord, may occur causing severe weakness and incoordination.
Total vitamin B12 is a low cost test that is widely available. However, total vitamin B12 tests have poorly defined ranges, and serum B12 levels do not always correlate with intracellular B12 levels. Tests for active B12 and Methyl Malonic Acid (MMA, a functional marker of B12 deficiency) may also be available but are expensive, have longer turnaround times, and still have limitations.
Please refer to the RUH clinical guideline for further guidance.
Webpage updated: December 2024
Links:
» Vitamin B12 Deficiency
