Unexplained anaemia and/or macrocytosis have traditionally been the indications used for suspicion of vitamin B12 deficiency. However, the article by Lindenbaum et al ( N Engl J Med 1988;318:1720-1728) demonstrated that more than 25% of patients with neurological manifestations of vitamin B12 deficiency have either a normal haematocrit or mean cell volume (MCV), or both. In fact elevated MCV are in most cases related to other conditions (alcoholism, liver disease, drug use). Also, even when there is metabolic evidence of B12 deficiency, MCV often is within the normal reference range. Absence of macrocytosis in B12 deficiency may also be encountered in patients with concurrent iron deficiency.

Normal red blood cells	Oversized red blood cells

The importance of examining the peripheral blood smear is often emphasized. The presence of hypersegmented neutrophils has been considered to be of high diagnostic accuracy but there are other non-specific causes (eg iron deficiency anaemia). Examination of smears (by haematologists) is also subjective and not suitable for high volume testing.

News

Coming Soon !  The full video recording of the Euromedlab 2007 Active B12 workshop will be available in the next few weeks, register for your copy.

Live CME Web Conference on vitamin B12 deficiency, Prof. Ralph Green, Dec 13th 2007, register now.

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Meetings

8-11 December, 2007
American Society of Hematology, Atlanta, booth 544
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