Abstract
A low vitamin B12 level is a common finding, and interpreting its significance can be difficult. A low level should never be ignored because deficiency may be responsible for occult haematological or neuropsychiatric disease.
Key Points
Low vitamin B12 levels do not always indicate deficiency, but they should be investigated.
Low vitamin B12 levels are common in elderly patients, but the clinical significance may be difficult to determine.
It is possible that vitamin B12 deficiency may be responsible for cases of minor cognitive impairment, as well as the more classic neurological manifestations.
There is concern that the widespread use of folic acid therapy and dietary supplementation may precipitate clinical disease in individuals with occult vitamin B12 deficiency.
Vitamin B12 assay results should always be interpreted in relation to the clinical context
