Pernicious Anaemia Society

Low ferritin, vitamin d deficiency and 'grey area' B12

I've just had the results of Friday's blood tests back (the IFA test is not back yet, but I had that shortly after my B12 injection so I don't know if that will be particularly informative anyway). I am low on Ferritin and Vitamin D deficient - does this suggest an absorption problem? Could this be related to B12 deficiency? I am feeling a lot better with very reduced neuro symptoms (touch wood) after having 8 x B12 injections with a few more in the pipeline (my B12 was 228 on a previous blood test, so a 'low normal'). I take 5mg per week folic acid supplements to counteract the methotrexate (for my RA).

I would be really grateful for any feedback or advice.


Serum C reactive protein level < 4 mg/L [0.0 - 6.0]


Erythrocyte sedimentation rate 11 mm [3.0 - 9.0]

Above high reference limit

Full blood count

Total white blood count 4.7 10*9/L [3.9 - 10.2]

Red blood cell count 5.00 10*12/L [3.9 - 5.2]

Haemoglobin concentration 126 g/L [120.0 - 156.0]

Haematocrit 0.396 L/L [0.355 - 0.455]

Mean cell volume 79.6 fL [80.0 - 99.0]

Below low reference limit

Mean cell haemoglobin level 25.4 pg [27.0 - 33.5]

Below low reference limit

Red blood cell distribution width 14.5 % [11.0 - 16.0]

Platelet count - observation 269 10*9/L [150.0 - 370.0]

Plateletcrit 0.210

Mean platelet volume 7.9 fL

Neutrophil count 2.28 10*9/L [1.5 - 7.7]

Lymphocyte count 1.89 10*9/L [1.1 - 4.5]

Monocyte count - observation 0.26 10*9/L [0.1 - 0.9]

Eosinophil count - observation 0.12 10*9/L [0.02 - 0.5]

Basophil count 0.05 10*9/L [0.0 - 0.2]


Serum magnesium level 0.85 mmol/L [0.7 - 1.0]


Serum C reactive protein level < 4 mg/L [0.0 - 6.0]

Serum ferritin level 7.5 ug/L [10.0 - 291.0]

Below low reference limit

Ferritin rises to an unpredictable extent with the acute phase

response. If CRP is over 30 mg/L, the ferritin result may be high and



Serum total 25-hydroxy vitamin D level 22.6 nmol/l

***Please note change of 25-OH vitamin D method with effect from


Ranges below relate to TOTAL 25-OH Vitamin D

Below 30 nmol/L is deficient

30 - 50 nmol/L: may be inadequate in some people

Above 50 nmol/L: is sufficient for almost the whole population

There is some evidence that levels nearer 75 nmol/L may be beneficial

for the frail elderly at risk of falling (see CUH Trust Guideline)

Above 500 nmol/L: Toxicity likely

For advice on management please see NOS publication :

Vitamin D and Bone Health: A Practical Clinical Guideline

for Patient Management and/or CUH Trust guidelines Ca

and Vitamin D supplements to adults with GFR>30mL/min/1.73m2

Thyroid function test

Serum TSH level 3.67 mU/L [0.35 - 5.5]

Serum free T4 level 12.7 pmol/L [10.0 - 19.8]


Serum folate level 10.85 ug/L [> 5.38]

Serum Folate Reference Range = Greater than 5.38 ug/L If the patient

cannot be fasted be aware that a folate rich meal, eaten less than 3

hours prior to venesection, may increase serum folate concentrations.

11 Replies

Hi rebs48 I'm not sure that the levels of B12 have any effect on the IFA test.

The bit about the Folate levels is interesting and I suggest you may need to keep an eye on it as it is essential to process the B12 you are having injected.


having the IFA test shortly after an injection is the one instance when it is prone to give a false positive - recommended not to do the test within one week of supplementation

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Hi rebs48. So...

Haemaglobin concentration and Haemocrit are low in the reference range - indicative of low iron, B12 and folate but..., they're slightly improved when read against your last set of results (111 up to 126 and 0.34 up to 0.396, respectively).

The MCV and MCHC are both below the reference range - indicative of iron deficency anaemia but again, both are improved from your last results (78 up to 79.6 and 24.4 up to 25.8).

ESR is slightly raised but not to a significant level - most likely due to anaemia rather that active inflammation since it's very low and your CRP is siting nicely in its own range (incidentally, CPR is more reactive that ESR and is not affected by anaemia).

Ferritin - deficiency - again, iron deficency anaemia. Level needs to be 80 - 100 to be optimum (though your GP may think a much lower level is acceptable - it's not. Needs to be optimum to get the best out of injections and most B12 deficient feel very ill with a level lower that 80.

GP should prescribe three month course of iron supplements the check ferritin levels three months after course to ensure levels being maintained (a full iron panel would be better that just ferritin as ferritin can be low and other iron levels high - not something to have). Best to supplement iron via GP as you need high dose and not advisable to do unless u dear medical supervision.

Vitamin D deficient - perhaps GP will prescribe supplement?

Folate looks on the low side (though difficult to tell 'cause it's one of those ridiculous references that fail to give the full range - sorry - short of time so can't look it up at the moment). But it sup on last time (was 8.4, now 10.85). Folate levels - aim for top third of reference range. Your GP may not know this.

So...your GP should prescribe iron supplements (and perhaps consider a slightly higher dose of folate - B12 injections will use it up more quickly, especially on the neurological regime - thibking here of the methotrexate issues also.

Hope your GP is continuing your B12 injections following the loading doses. You have neurological symptoms so should then receive every other day injections until no further improvement. Your GP may not know this - come back if you need more help with getting continued treatment.

And yes, the low ferritin, folate and B12 could be indicative of absorption problems - most cases of B12 deficency are due to an absorption problem. Unless another causative factor is found (i.e. Perhaps a drug impeding B12 absorption or heliobactor infection) - an absorption issue is the most common cause.

Your GP should not stop you injections if your anti-IF antibodies is negative (it's only 50% accurate so you could still have PA - it's called anti-body negative PA - your GP has probably never heard of this - unless you're very lucky 😄).

Anyway rebs48, hope all continues well...lets us know how you get on and post again if you need more help 👍


Brilliant reply again Foggyme


Why thank rebs48. But forgot to say...the fact that you are having symtpom relief from the B12 injections is what your GP should be guided...not whatever your serum B12 levels were - or may be in the future (should be high with all those lovely jabs 💉💉).


P.s. I'm laughing at the catch twenty two of the anti-IF antibodies test...negative equals 50% wrong / positive equals potential wrong ('cause of the jabs)...

Laughing in a here we go again kind of way...😖


Are you back on the nitrous oxide again Foggyme?

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Shh...don't tell 😅😂🤣🙃

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Foggyme My IFA test has just come back - I'm assuming this is negative?:


Intrinsic factor antibody level 2 u/ml [0.0 - 24.0]


Yep...negative...or should I say 50% negative.

If you have trouble with your GP, might be worth reminding him / her that B12 deficency has other causes too..? of course, you could still have PA...

So...they shouldn't try to stop your injections simply because the test is negative...

Symtpoms relief is what counts, not test results (this or the serum B12).


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Thanks for this, Foggyme . It's odd because my neuro symptoms are definitely improving, so I'm certain that I am B12 deficient. Do you think it's worth asking for a referral to a Gastroenterologist to check out coeliac or Crohn's disease?

I'm concerned that this could drag out indefinitely although I realise that auto-immune disease can be 'grey area' medicine...

Your help has been invaluable, so genuine thanks :)


Hi rebs48. problem 😄.

No, it's not odd...the anti-IF test is notoriously imprecise. Martyn Hooper, the Chair of the Pernicious Anaemia Society tested negative twice before he got a positive test result...and he most certainly lay always had PA.

Your low ferritin and folate would indicate that there is some sort of absorption problem going on...and your GP should want to try and get to the bottom of this so...yes, a referral to a gastrologist would be appropriate. Coeliac's and Crohn's disease can also be a cause of B12 deficiency. And an endoscopy would enable a 'look see' to check if you have gastric atrophy (PA causes this).

And you may well have a 'masked' macrocytic anaemia (what your GP would expect to see in PA - wrongly) - masked because of the methotrexate you are taking for your RA.

Just wondering...did your GP prescribe a course of iron supplements - your ferritin was very low.

And I assume you're still taking the folate? It was still on the low side and more will be used up mediating the B12 may need to take higher doses - your GP should check levels regularly.

And yes, I'm certain you were (still are) B12 deficient. The fact that you are responding to the injections is a sure indicator of that.

Also - hope your GP is keeping you on alternate day injections (the neurological regime)? This should be continued until you are sure that there is no further improvement.

Once treatment with injections has started, serum B12 levels are no indicator of the effectiveness of treatment. Your GP may not know this.

Be sure not to come off the neurological regime until you are absolutely sure that you are (and have been) symtpom free for some's a big stretch from every other day to every eight weeks (unfortunately the only regime current guidelines allow for). Once off the neurological regime it might be very difficult to get a GP to re-prescribe it - 'cause most don't really understand B12 deficiency and so don't understand that frequency requirements can be so different for each individual.

Once on a regular regime (after the neurological regime), the only measure of effectiveness is symtpom relief and if symtpoms are returning before the next injection is due, then that's an indicator that injections are needed more frequently.

The main thing is that you have enough B12 to make and keep you well.


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