Writing to your Doctor

If you are struggling to achieve a diagnosis or the correct level of treatment for B12 deficiency please use this page to help compile your personalised letter to your doctor.

Many patients are in desperate need of help and if your doctor does not fully understand your condition, then it often becomes essential for you to try and help your doctor to update their knowledge in order to treat you properly and as an individual. This can perhaps be best addressed in the form of a letter.

If you’d prefer me to help with this please visit the Work with me page for more information.

Start here - the standard information you will need for your letter...

If you have a ‘Patient ID’ include this at the head of your letter along with the necessary personal details such as date of birth.

To start your letter It really helps to outline your (or a loved one’s) symptoms and to state that you are writing because you are concerned that you are at risk of serious injury if you are not treated correctly. Use the signs and symptoms page and if necessary, the children’s page to do this.

Then outline how your condition affects your quality of life (your child or other family member). It may not be obvious to your doctor just how much you/they are struggling.

You may want to include how this affects your daily life, the impact on your family, your children, your finances?

Are you unable to work?
Have you had repeated sick leave?
Repeated doctors appointments?
Have you lost your job?

School/ University – Are you behind or unable to study?
Have you been late and warned about poor attendance?

Is your ability to carry out simple tasks drastically reduced?
Let the doctor know when you started to feel unwell, it may be years before.

Do you have repeated infections?

Point out your related conditions (e.g any autoimmune conditions – thyroid disorder, vitiligo, etc) or indeed, those conditions which are commonly misdiagnosed in place of B12 deficiency. You will find these on the Who is at risk page.
A family of history of stroke or cardiovascular problems is also key, high homocysteine levels are indicative of B12 deficiency.

It would also help to point out if you have a family history of B12 deficiency/pernicious anaemia.

Causes – the drugs you take may have caused your inability to absorb B12 and your doctor may not be aware of this. Please check the Causes page. List those which apply to you. It may be that you have had surgery which caused your deficiency, perhaps, your doctor is unaware of this connection.

Below you will see further scenarios which may apply to your situation clicking on each relevant point will take you straight to the text required.

Suggested text for you to use in your letter will appear in Green below -*Asterisks denote where you must delete text or add your personal information. There are also ‘Supporting documents’ which you might like to add. 

1. Neurological symptoms - suffering from under treatment...

Some doctors do not fully implement the treatment guidelines which allow for unrestricted every other day injections until neurological symptoms stop improving.

These doctors fail to understand that the symptoms can be reversed if B12 deficiency is treated aggressively for long enough. Many patients are given 6 loading dose injections and then are told that they can have their next injection three months later.

Three monthly injections are not anywhere near regular enough for the majority of patients. Unfortunately there is no clinical evidence to support this paltry maintenance dosage, it came about following GP audits and not care for patients. Patients should be treated as individuals but sadly many doctors fail to personalise treatment and hear their patient’s pleas for more injections.

Suggested text
I am concerned that I am not being treated correctly for my neurological symptoms. I know that to have the best chance of completely reversing these I need to be treated as per NICE and BNF Guidelines 9.1.2. which state that injections should be given every other day until symptoms stop improving. Please note; there is no time limit on this and I understand that in order to reverse neurological symptoms it could take some time. 


Supporting documents
‘Parenteral (Intramuscular or Subcutaneous) ‘Administration of parenteral crystalline cobalamin has been the standard treatment protocol for decades.78,79 Few side effects have been reported, and patient acceptance is generally high. Anecdotally, the subcutaneous route causes less burning than does the intramuscular route (Carmel RA, New York Methodist Hospital [personal communication] 2006-2007).
Regimens for parenteral administration vary.
An approach suggested by Stabler and Allen is 1 milligram (1,000 ֧) weekly for 8 weeks, then once monthly for life.’ ‘Some providers have used quarterly injections after the initial dosing protocol. However, experts state that in pernicious anemia or severe malabsorptive deficiency, quarterly injections are not sufficient, noting that cobalamin levels start to fall prior to the 1 month follow-up (Allen RH. University of Colorado [personal communication] 2006-2007).’

You may want to add information on the Petition requesting that UK patients be allowed to buy injectable B12 from pharmacies as in other countries.

2. B12 documentary by Elissa Leonard - (this link has gained many people help and understanding from doctors who lack knowledge of B12 deficiency...

Suggested text
I wonder if you would please consider watching even the first 5 minutes of this excellent film? It demonstrates just how serious this deficiency is, how it is commonly misdiagnosed and under treated. www.youtube.com/watch?v=BvEizypoyO0

3. If you are being refused B12 deficiency diagnostic tests...

Sometimes our doctors can mistakenly believe our symptoms can be attributed to a pre existing condition, diabetic neuropathy for example, can be confused with the tingling and numbness (paresthesia) caused by B12 deficiency.

Despite many conditions sharing the same symptoms, if you already have a diagnosis of fibromyalgia, Chronic fatigue syndrome (CFS), or bipolar etc, your doctor may be reluctant to test for B12 deficiency. This ignorance could cause real harm to an undiagnosed B12 deficient patient. Please use this link – Misdiagnosis

Suggested text
I am concerned that I have been refused B12 testing. I know I have many symptoms and I want to be given the chance to either confirm or rule out this very common deficiency. I know I could be seriously harmed if I am deficient and remain undiagnosed and untreated.

*****I am taking Metformin and Omeprazole and I know that these drugs cause B12 deficiency.***

I wonder if you would please consider watching even the first 5 minutes of this excellent film?It demonstrates just how serious this deficiency is, how it is commonly misdiagnosed and under treated.


4. Mental health...

Many clinicians remain unaware of the enormous impact low B12 has on mental health and although depression can be one of the first presenting symptoms – it appears that B12 deficiency is not routinely tested if you have a mental health diagnosis.

Suggested text
‘My mental health is very poor and I have found that there has been a well documented link discovered over a hundred years ago between mental illness and low B12 I add this pdf of journals for your information. www.www.b12deficiency.info/media/1010/psychiatric-symptoms-v3.pdf

I know that B12 deficiency is not routinely tested for in patients with mental health problems but I am taking increasing levels of antidepressants and I understand that there is reduced efficacy in patients with low B12.’

For more information please see – Mental Health

Supporting documents: **********

5. If you or your child are experiencing symptoms but have a 'within range' serum B12 result...

Sometimes our doctors rely just on the numbers of the flawed B12 serum test which is very often the only diagnostic test used. There is also a lack of understanding of ‘functional B12 deficiency’ where there is a transport problem with problem with the proteins that help transport vitamin B12 between cells. (see more in supporting documents below).

In addition some reference ranges used by labs are extremely low, this means that many dangerously deficiency patients remain undiagnosed.

If you are experiencing symptoms of B12 deficiency – whatever your level then you could be at risk of neurological damage. It is essential symptomatic children are fully tested using MMA and homocysteine.

It is important to understand that the B12 serum test records both active B12 which can be used by the body and inactive B12 which can’t. The test may record as much as 80% of inactive B12 otherwise known as B12 analogues.

Please see this link Children Neurological symptoms may not be reversed in prolonged deficiency, particularly in very young children when the nervous system is still developing. Documents below support this fact.

Suggested text
I am within range but I am heavily symptomatic. I have family members with B12 deficiency/pernicious anaemia so I know there is a chance that I could also be at risk.

***I am really concerned about my child I have noted the ‘red flags’ and symptoms from this page www.www.b12deficiency.info/children/).

Please would you read this NEQAS Alert which clearly warns of ‘False normal B12 results and the risk of neurological damage’.

Please see this from the NHS website regarding the serum B12 blood test – 


‘A particular drawback of testing vitamin B12 levels is that the current widely-used blood test only measures the total amount of vitamin B12 in your blood.  This means it measures forms of vitamin B12 that are “active” and can be used by your body, as well as the “inactive” forms, which can’t. If a significant amount of the vitamin B12 in your blood is “inactive”, a blood test may show that you have normal B12 levels, even though your body cannot use much of it.  There are some types of blood test that may help determine if the vitamin B12 in your blood can be used by your body, but these are not yet widely available’.

Please consider a therapeutic trial and in addition please test my homocysteine and MMA levels as these are more accurate indicators of B12 deficiency. Please see www.www.b12deficiency.info/testing/

Supporting documents

Functional Vitamin B12 deficiency


‘Some people can experience problems related to a vitamin B12 deficiency, despite appearing to have normal levels of vitamin B12 in their blood.
This can occur due to a problem known as functional vitamin B12 deficiency – where there is a problem with the proteins that help transport vitamin B12 between cells. This results in neurological complications involving the spinal cord’.


‘We describe a case of functional vitamin B12 deficiency where the repeated measurement of a serum B12 level within the normal range led to delay in the diagnosis of subacute combined degeneration of the spinal cord, and possibly permanent neurological damage as a result….’


Vitamin B-12 is of singular interest in any discussion of vegetarian diets because this vitamin is not found in plant foods as are other vitamins. Many of the papers in the literature give values of vitamin B-12 in food that are false because as much as 80% of the activity by this method is due to inactive analogues of vitamin B-12.

A case of subacute combined degeneration with normal serum vitamin B12 level
‘These clinical and laboratory findings support the diagnosis of SCD with normal serum level of vitamin B12 in our case, suggesting that the level of vitamin B12 in serum does not always correlate with that in tissue and, therefore, SCD should not be excluded just only by the reason of normal serum vitamin B12 level’.

This Clinical Review from the BMJ  www.bmj.com/content/349/bmj.g5226 on B12 deficiency states:

“There is no ideal test to define deficiency and therefore the clinical condition of patients is of the utmost importance.”


“If the clinical features suggest deficiency then it is important to treat patients to avoid neurological impairment even if there may be discordance between the results and clinical features”


‘It should be remembered that serum B12 is not always an accurate reflection of deficiency at a cellular level.[4] It is perhaps for this reason that some patients become symptomatic if the frequency of their injections is reduced, despite having normal serum B12levels.’



6. If you think you may have been misdiagnosed...

When your B12 deficiency symptoms are obvious but you think you have been mistakenly diagnosed with another condition. For more info see the misdiagnosis page.

Suggested text
I have been diagnosed with *CFS*Fibromyalgia*Bi polar* etc* which I understand can be a misdiagnosis of vitamin B12 deficiency. I have many symptoms and I would like to have this confirmed or ruled out in order that I have the best chance of recovery. please see here. www.www.b12deficiency.info/misdiagnosis/

7. Toxicity - If you are being told that too much B12 is harmful...

Suggested text
Despite being told that too much B12 is harmful I understand that there is no known toxicity and that hydroxocobalamin is used in extremely high doses as a treatment for cyanide poisoning. B12 is a water soluble vitamin, and the body needs constant replacement. Please see below documents –



8. If your doctor wants to stop your injections and replace with oral tablets...

Some doctors mistakenly believe that once serum levels are improving then you no longer require injections and can survive on low dose cyanocobalamin oral tablets. However, unless you are vegetarian/vegan and your deficiency is PROVEN to be dietary then you must not be prescribed oral cyanocobalamin tablets.

Suggested text
Your decision to stop my B12 injections and replace them with low dose cyanocobalamin tablets is disturbing. They will be completely useless for me. My diet includes a healthy level of animal products so clearly I cannot absorb B12 from food. am not vegetarian or vegan.

Furthermore Nice Guidelines state –
‘Be aware that oral cyanocobalamin is suitable only for the small number of people with proven dietary deficiency of vitamin B12. I ask that you please consider all I have said here, and reinstate my vital B12 injections at the frequency that BNF 9.1.2. and NICE Guidelines allow for.

Supporting documents

9. If your doctor doesn't understand that B12 deficiency is as serious as PA and requires the same treatment...

Suggested text
I understand that my test result does not confirm that I have PA (pernicious anaemia). I understand that negative GIFA (Gastric intrinsic factor antibody) and GPCA (Gastric Parietal cell antibody) tests are low sensitivity and miss many patients who have numerous family members with PA.

In addition PA is just one cause of B12 deficiency, they are as serious as each other and require the same treatment. There are many other causes and from the list here, www.www.b12deficiency.info/causes I can see that I am taking *** two drugs, Metformin and Omeprazole,(enter applicable details)****** which affect my ability to absorb B12 from food.

10. Asking to be taught to self inject...

Suggested text
I have neurological symptoms, I know I need injections every other day until my symptoms stop improving, as per NICE and BNF Guidelines. I do understand that frequent injections would take up surgery time and will be difficult and time consuming for me. Please consider teaching me ***(or a family member) to do my own injections so that any burden on the practice is greatly reduced.

11. Folate and iron deficiency...

Some patients find that they feel no better despite loading doses and follow up treatment. Mostly this can be down to under treatment of B12. It is quite common to have a co existing folate and iron deficiency. The reference ranges are often set very low for both these levels meaning that many patients have ‘within range‘ results. However optimum levels of folate and ferritin (iron storage) are required to gain the best from B12 injections.

Suggested text
I am struggling to function despite my loading doses *** (enter your treatment details)**** and understand that I require optimum levels of folate and ferritin in order that I can gain the best from my B12 injection. I am very low in both so I ask that you please advise me on the best supplements to help me to raise these levels. I also understand that ferritin and folate levels require monitoring periodically.

Please see the Treatment page

Supporting documents
Diagnosis and treatment of vitamin B12 deficiency. An update.
 http://haematologica-thj.org/content/91/11/1506.full.pdf…importance of monitoring Ferritin and folate levels once B12 therapy started.

Once vitamin B12 has been administered, the increase in red cell production will increase the demand on iron stores and, therefore, it is important to monitor – and correct – any signs of iron deficiency. Secondly, a folate deficiency may be unmasked as demonstrated by a drop in plasma folate after initiation of vitamin B12 treatment.

Care should be taken not to give folic acid(instead of B12) to any patient who is B12- deprived, as this may result in fulminant neurological deficit. 
Folic acid levels should be measured to exclude deficiency, which may co-exist with B12deficiency. Red cell folate is a better guide to deficiency than serum folate. B12 deficiency may result in increased serum folate levels but reduced red cell folate levels, because of the effect on intracellular folate metabolism. [9] Combined deficiency usually results in both reduced serum folate and vitamin B12 levels.

12. Macrocytosis - Large red blood cells...

Some doctors do not understand the fact that macrocytosis (large red blood cells) is an advanced symptom of B12 deficiency and mistakenly think that no treatment is required unless it is present.

Supporting documents
Absence of anaemia – macrocytosis

13. If your fertility - male or female has been affected...

You will require more B12 injections, if you have neurological symptoms one injection every quarter will not be enough to help aid conception. Your B12 injections will be as important as good folate levels. In addition folate supplementation is known to mask B12 deficiency. Please see the journals below.

Supporting documents




14. If you are pregnant...

Pregnancy in a B12 deficient mother places a huge demand on B12 levels. You will need adequate supplementation in order to keep your levels up.

Supporting Documents



15. If you have suffered a stroke or cardiovascular problem...

High homocysteine levels are often found in patients who have suffered a stroke or heart condition. This amino acid rises to toxic levels in patients with low B12.

Supporting Documents

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