In July 2015, Clara Plattel (founder of B12 Deficiency Research Group NL, predecessor of the B12 Institute) participated in the 10th One Carbon, Homocysteine ​​and B-Vitamins Conference, held at the Medical Faculty of the University of Nancy. Several top scientists (mostly biochemists) from around the world presented interesting results from their research field and there was plenty of room to share research and clinical experiences.

One topic kept coming up: the need for rapid diagnosis and treatment of B12 deficiency because of the complications that can arise from untreated (under-treated) vitamin B12 deficiency. A complication here is that the classic presentation of B12 deficiency (Pernicious Anemia) occurs less and less often. This correlates with our unpublished data: 18.5% of the women with a B12 value <150 pmol / L only had anemia (anemia).

Anemia as the first biomarker for B12 deficiency (even for Pernicious Anemia) is completely inadequate. Unfortunately, many treating doctors still assume this.
Below you can read the summary of Dr. Ralph Green, held at the conference in Nancy. He also points out the need for timely diagnosis and treatment of B12 deficiency and the deception that can occur because the symptomatology of B12 deficiency is so extensive and varied.

In addition to Dr Green’s account, we would like to mention the importance of observing the clinical symptoms that occur. In addition to checking the blood values, a good and extensive anamnesis is necessary.


The protean faces of vitamin B12 deficiency – master of disguises

Dr. Ralph Green, 
University of California, Davis, CA, USA

Background: Vitamin B12 deficiency has many faces. The classical features of established B12 deficiency are well described in the paradigm of pernicious anemia. Typical manifestations consist of a macrocytic anemia associated with glossitis, jaundice and neurological complications. Neurological complications usually include sensory and motor spinal cord involvement. In recent years atypical presentations have been identified with greater frequency. In a patient with suspected B12 deficiency, confirmation of the diagnosis is based on the results of one or more laboratory tests. Missed or delayed diagnosis may result in irreversibility of an otherwise treatable disorder. Reasons for the protean manifestations of B12 deficiency can be explained or deduced from a consideration of underlying pathogenetic mechanisms. Because the neurological complications of B12 deficiency can be devastating and are preventable as well as often correctible, it is important for physicians to have a high index of suspicion of the disease and to carry out necessary tests to either identify or exclude its presence.

Objective: The goal of this presentation is to identify the different faces of B12 deficiency and to show examples of mechanisms that disguise or mask its appearance.

Design: Reasons for masking of the classical features of B12 deficiency are examined through the use of case examples and discussion of the mechanisms responsible for obscuring typical features of the condition.

Results and Conclusions: Several common causes of masking of the features of B12 deficiency are identified:

  1. Macrocytosis may be masked by a coexistent microcytic process such as iron deficiency.
  2. Anemia may be absent and the only clinical manifestation of B12 deficiency may be neurological. This may be attributable to adequacy of or treatment with folic acid, which can ameliorate the hematological effects of B12 deficiency.
  3. The neurological manifestations may also take different forms, such as dementia and visual or autonomic disturbances, which may result in misdiagnosis of other neurodegenerative diseases including Alzheimer’s disease and multiple sclerosis.
  4. Plasma B12 level may be spuriously normal because of increased levels of the binding protein haptocorrin. The availability of new combinations of diagnostic tests that enable ascertainment of the existence of biochemically significant B12 deficiency greatly facilitates diagnosis by making it possible to determine whether or not a patient is, in fact, B12 deficient.


We also like to state: don’t forget to look at the clinical signs.

Abstract taken from:

Scientific Program of 10th International Conference Metabolism, Vitamins-B and homocysteïne, Nancy Faculty of Medicine, July 7th -11 2015

On behave on my team, I like to express my gratitude to:

  • Dr. Ralph Green, clinical pathologist and Professor at the Department of Medical Pathology and Laboratory Medicine UC Davis Medical Center, for his personal permission to publish his abstract on our website.
  • Dr. Jean-Louis Guéant, Professor at the Medical Faculty of the University of Lorraine Nancy and organiser of the conference, for his kind permission to publish this abstract.

© Clara Plattel and © Ralph Green on his sited comments