Pernicious Anaemia Society
14,189 members10,164 posts

Introducing myself and question about test results

Hello everyone and nice to e-meet you!

I was referred to you knowledgeable lot by a member of a thryoid forum I'm part of.

I'm a 29 year old with an underactive thyroid and for the past almost-three years I have been suffering with recurring extreme tiredness, feelings of hot and cold, nausea, skin crawling, weak muscles (especially legs), high irritability and a slumping libido. I feel that this all the result of either my existing condition or a closely related one, but my doctors have not been very helpful and now that one of them has referred me to a Chronic Fatigue clinic, even less so. Meanwhile my health seems to be getting worse.

Anyway, I got a thyroid function test done privately, and one of the members of the thyroid forum thought my B12 levels suggested Pernicious Anaemia. I was just wondering if any of you guys agreed and, if so, could suggest what I should do next?

These are my results:

VITAMIN B12: 186 pmol/L 140.00 - 724.00

FOLATE (SERUM): 9.44 ug/L 3.89 - 26.80

FERRITIN: 201.3 ug/L 30.00 - 400.00

25 OH VITAMIN D: 85.93 nmol/L 50.00 - 200.00


FREE THYROXINE: 17.57 pmol/L 12.00 - 22.00

TOTAL THYROXINE(T4): 76.1 nmol/L 59.00 - 154.00

FREE T3: 4.22 pmol/L 3.10 - 6.80



CRP - HIGH SENSITIVITY: 0.2 mg/L 0.00 - 5.00

Thank you so much for your help and time.

2 Replies

The serum B12 test is, unfortunately, not the best one when it comes to interpreting results - its certainly a long way from being a single measure that can be used to define whether you have a B12 deficiency or not.

People vary significantly when it comes to how much B12 they need and the amount in your blood is only a fraction of the picture because there is a lot of processing that goes on with B12 and things can go wrong at every stage - absorbing it in your gut and getting it into your blood, getting it from your blood to cells, and then converting it to the relevant form for whichever process the cell needs it for.

The test normal range is likely to miss 25% of people who are B12 deficient but also pick up 5-10% of people who aren't deficient if used as a single measure so needs to be interpreted in context. Many GPs are aware of the link between B12 and macrocytic anaemia but don't really understand the link properly and aren't aware that 30% of people with B12 deficiency don't develop macrocytic anaemia until the deficiency is quite far advanced. The result is that many fail to appreciate just how important evaluating symptoms is when looking at a B12 deficiency. Where there are multiple conditions already present with symptoms that overlap with B12 deficiency evaluating symptoms also becomes rather difficult and many GPs tend not to go beyond the first condition that they hit and consider that there might be more than one thing going on.

I am telling you this because the chances are that you are going to need to work with your GP and raise their background knowledge in order to get treatment.

Your B12 result above - given your symptoms - is likely to be indicative of a B12 deficiency.

I am assuming that you aren't a vegan / someone who eats very little meat/fish/dairy/eggs. B12 is only found in animal products or food that has been specifically fortified so not eating any animal products is a particular risk for a dietary deficiency, which is resolved by supplement much smaller doses than are need if the problem isn't dietary.

The mechanism that the body uses to absorb B12 from food is very delicate - and can go wrong very easily. PA is an autoimmune condition that attacks the specific mechanism that absorb B12. Other absorption problems - such as coeliacs and crohn's can also have a significant impact on your ability to absorb B12 from your food. There are also a load of drug interactions that can affect B12 absorption including some types of contraceptives, metformin used to treat diabetes, NSAIDs, and PPIs used to treat high stomach acidity - the later can be particularly problematic as the symptoms of low stomach acidity (another thing that can significantly impact on your ability to absorb B12) are more or less identifical to high stomach acidity so PPIs can be used in treating a mis-identified low stomach acidity problem, making the situation worse. There are also infections - notably H Pylori - that will affect absorption and lead to a deficiency.

Your tests above are indicative of a B12 absorption problem but don't actually give any information on what that problem is - your folate is a little on the low side but your ferritin is mid range suggesting that you probably don't have a general absorption problem - but ferritin is only one indicator on iron deficiency and evaluating that would need a full blood count.

I can't comment on thyroid related items and presume that TUK have covered those.

There are a few other tests that can be used in looking at a B12 deficiency - MMA and homocysteine levels will be raised if there isn't enough B12 available at the cell level.

Suggest that you discuss results with your GP - sharing the information above on the limitations of the serum B12 test. Ask for MMA testing as a further check if necessary. You can also ask about testing for possible absorption problems and evaluate any potential drug interactions ... and make sure that you provide a full list of symptoms.



Can you ask the Dr to check for antibodies to Intrinsic Factor and GPC? These tests are not reliable but can help if they prove you have the antibodies.


You may also like...