If somebody has a serum B12 level of 70 pmol/L, combined with a macrocytic blood count and anaemia, levels of folic acid levels of 3 nmol and serious (neuro) mental  symptoms, it should not be hard to arrive at the diagnosis of B12 and folate deficiency. We use the word ‘should’ on purpose, since in the Netherlands eight people unecessarily die of B12/folate deficiency every year (CBS, Feb. 2016).

It is, however, harder to make the diagnosis for patients with a serum B12 level of 100 pomol/L, without anaemia, and who has trouble walking because of muscular pains in the femurs, with tingling feet, joint adhesion pains, who has a mild depression, blurry vision and has formerly been diagnosed with hypothyroidism.

B12 deficiency diagnosis is complicated

According to the Dutch College of General practitioners (NHG) there is no ‘golden standard test’ to determine a functional B12 deficiency. We should stress here that  symptomatic B12 deficiency doesn’t always show hematologic disorders. Anaemia with high levels of MCV – the traditional diagnostic tool – is absent in many cases. Literature and practical evidence shows that the neurological symptoms may even be more severe when patients do not suffer from anaemia.

World Health Organisation 

The standard that is generally applied by the WHO (World Health Organisation) is a minimum serum total B12 level of 150 pmol/L; therefore, a serum b12 < 150 pmol/L means that there is a B12 deficiency. There are people with a low serum B12 level (<150 pmol/L) who don’t show any symptoms at all; although they are considered deficient by the WHO, as yet, they are not being treated by the B12 Institute. We do give them information as a preventative measure.

Researchers have started to raise concerns about the long-term consequences of patients with a low serum B12 level without symptoms. In Israel, everybody over 65 is screened preventatively for B12 deficiency. If they show symptoms and serum B12 levels below 150 pmol/L and between 0 and 200 pmol/L, they are treated with injections immediately.

Literature studies prove that values between 150 and 300 pmol/L may certainly point to a functional deficiency, irrespective of the age of a person. If a person has such values, combined with symptoms, MMA and homocysteine levels can be included, since these levels may be raised as a result of a functional B12 deficiency. Recent research results, however, show that patients with B12-deficiency-related symptoms and serum levels between 150 and 200 pmol/L benefit from suppletion, despite the MMA values. This is also seen in clinical practice circumstances  

The Dutch College of General practitioners (NHG) points out that testing for B12 values after or during B12 supplementation makes no sense, since during that process the biochemistry does not correlate with the symptoms.

Testing for MMA and homocysteine after suppletion, however, can be useful: decreased levels may show that the treatment has been successful. We are working towards a protocol for determining a functional deficiency and clearly mapping out the symptoms and the severe consequences of B12 and folate deficiency. Therefore it is necessary to consider the symptoms of the patient, the medical history of themselves and their relatives, even with levels between 150 and 220 pmol/L (marginal or subnormal) or between 220 and 300 pmol/L (normal)

Diseases with similar symptoms (such as e.g. thyroid diseases, Lyme disease) must be excluded before patients approach us.

Hematology (blood count)

For a patient’s medical history earlier tests are relevant as well, but we do need the most recent lab results. If results are not up-to-date or incomplete we can have you tested in the STAR-laboratory opposite the B12 Institute. During the care process we monitor certain values in cooperation with STAR or Erasmus MC laboratory. Costs will be on our account, since the test is part of our medical specialist care and falls within our DOT/ DBC (transparency of Diagnose -Treatment – combination policy).


All symptoms that have been observed in a patient, will be recorded, filed and submitted to your personal file.

Personal medical history

During your treatment we will take your personal medical history into account.  

Medical history of relatives

We will also take into account any relevant family medical history of genetic disorders.