HomeList of TitleSearchContact Us

Open Journal of Hematology

ISSN: 2075-907X
Volume 8, 2017

Indexed in:

Open Journal of Hematology, 2012, 3-2 [Case Report]

Pitfalls in the Diagnosis of Vitamin B12 Deficiency

Nataliya Mar1,*, David Askin2, Robert J. Klafter2
1 Department of Medicine, Lenox Hill Hospital, New York, USA
2 Department of Hematology and Oncology, Lenox Hill Hospital, New York, USA

Corresponding Author & Address:

Nataliya Mar*
100 East 77th street, 6 Blackhall, New York, NY 10075, USA. Email: nam244@nyu.edu

Article History:
Published: 20th September, 2012   Accepted: 20th September, 2012
Received: 30th May, 2012   Revised:  4th July, 2012

© Mar et al.; licensee Ross Science Publishers

ROSS Open Access articles will be distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided that the original work will always be cited properly.

Keywords: vitamin B12 deficiency, cobalamin assay error, methylmalonic acid, homocysteine, holotranscobalamin, empiric B12 replacement


Vitamin B12 deficiency is a well-described disorder with a spectrum of manifestations ranging from macrocytic anemia to neuropsychiatric disorders including depression, dementia, and subacute combined degeneration of the spinal cord. Lack of vitamin B12 arises from insufficient intake or malabsorption. In clinical practice, serum total cobalamin (Cbl) levels are the initial test of choice for detecting B12 deficiency as they are widely available and cost-effective. However, this test is limited in specificity and sensitivity, missing many patients within the laboratory “gray zone” of deficiency. Measurements of serum methylmalonic acid (MMA) and homocysteine (Hcy) levels, which accumulate in B12 deficiency, become useful when Cbl levels are equivocal but clinical suspicion remains high. Early vitamin B12 replacement is important in preventing potentially irreversible neurologic damage.

We report a case of a 75 year-old man presenting with symptomatic anemia, neuropsychiatric findings, and repeatedly normal serum cobalamin levels, eventually diagnosed with vitamin B12 deficiency due to pernicious anemia. This case highlights the potential difficulty in establishing this common diagnosis due to false-negative Cbl assay results. Given its high prevalence, vitamin B12 deficiency must be included in the differential diagnosis of patients with progressive neuropsychiatric findings and/or hematologic derangements as rapid diagnosis and supplementation may prevent permanent complications.

©2017 Ross Science Publishers