Pernicious Anaemia Society
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Red Blood Cells -advice needed

Hi all,

I was diagnosed with pernicious anaemia 4 years ago after a long battle with the healthcare system and it seems the fight continues. I was tested for B12 deficiency when I was 21 and it showed my levels were low then but was not acted on. I was told I had depression. ME, Chronic Fatigue and then was basically told it was all in my head - Feeling fatigued, pain in my legs, inability to concentrate, feeling the need too fall asleep on my desk by 2pm everyday! I finally decided to see a different GP who tested my B12 and told me that bad news was my b12 levels were 5 time lower than the recommended level but that she could treat me. That was 4 years ago and I am 33 and now receiving shots every 12 weeks.. I recently went back to the doctors as around 8 weeks I get the cloudy brain back and energy levels drop significantly. They kindly informed me that in Sept 2015 my red blood cells were shown to be enlarged (100) but I was not aware of this at the time, nor did they monitor or follow up with me. The doctor said she could not just increase my dose to every 8 weeks without testing me again so I had the test and low are behold my cells are still enlarged (increased now to 101.5).

I saw a different GP today to follow up from the recent blood tests and this one wants to test my B12 but my understanding was that would be pointless as it wont show low or high because I have the jabs!

The reason for this post is I am at my wits end! This foggy feeling has not started to affect my performance at work and I walked out of the surgery today feeling hopeless. The doctor actually asked me if I was depressed - of course I am!!

Do any of you know if my cells will always be large regardless of the shots? Or should i be pushing to know why they're still large?

I am going to book in to see the first GP as she seemed more receptive to the idea of me needing my jab every 8 weeks but she is not around until Oct 4th so any advice here would be greatly appreciated.

Thanks for reading my exceptionally long post!


14 Replies

Sorry that should read "HAS started to affect my performance at work"

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Hi sorry I'm not going to be much help but I'm going through the same thing you are just not as long as you have been going through it. Symptoms are tingling and pain in arms and legs and feet brain fog and shortness of breath.

Doctor told me it was my anxiety due to the fact that I'm getting married in four weeks I had to make her do a CBC and check my thyroid my thyroid came back normal and everything on my CBC was normal except my MCV was elevated 101.6 she called me and asked me to come back in for more blood tests she tested a bunch of different things and everything came back normal but my B12 was 292 as well as my MCV went down to 100.4 I read that the standard range for B12 is 200 - 1000 but I've also read that if you are in the range of 200 - 500 you are considered deficient and could show neurological symptoms I'm very frustrated and scared I sure hope you get the answers that you need :)

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I have no reply but wanted to add this sounds a lot like me. 2 weeks before and 2 weeks after my b12 quarterly shot ,I crash with all the symptoms of anemia and my blood results are always over large cells.

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Have a look at page 8 and page 29 in the "BCSH Cobalamin and Folate guidelines"

Page 8 gives details of UK b12 treatment. Page 29 outlines the recommended process GPs should follow with someone they suspect has B12 deficiency.

Have you ever had an IFA (intrinsic Factor Antibody) test which can help to diagnose PA (Pernicious anaemia)? The test is not always reliable and it is still possible to have PA even if IFA test is negative.


"The doctor said she could not just increase my dose to every 8 weeks without testing me again"

I think GPs can increase dose to every 8 weeks if a patient, who is B12 deficienct, has neuro symptoms. UK B12 treatment for those with B12 deficiency with neuro symptoms is loading doses every 2 days for as long as symptoms get better then injections every 2 months.

Do you have any neuro symptoms? See Symptoms lists below. I gave a copy of PAS Symptoms Checklist to my GPs with all my symptoms ticked.


Have you read Martyn Hooper's latest book "What You Need to Know About Pernicious Anaemia and Vitamin B12 Deficiency"? i gave a copy to mY Gps. This book is up to date with current UK guidelines.

Another B12 book I found helpful was "Could It Be B12" by Sally Pacholok and JJ. Stuart


Low B12 can lead to macrocytosis (enlarged red blood cells). Low folate can also lead to macrocytosis. Has your folate level been checked recently?

I am not a medic, just a person who has struggled to get a diagnosis.


Hi Sleepbunny,

Thanks for the incredibly informative post!!

The doctor I saw before my blood tests discussed increasing to every 8 weeks but then the one I saw today said my blood tests, hence my frustration!

I definitely show signs of nuro problems and thats what worries me the most! I have no memory of childhood or my early 20's and worry that my years of misdiagnosis and no treatment is the cause of that. Memory aside my foggy brain around 8 weeks means I struggle to function. I cant explain myself even though the word is on the tip of my tongue and I do not process information like I can when the fog is not there. This has really come to the surface lately and now feel depression setting in.

I haven't read either of those books but will certainly look into it, thanks.

They tested my folic acid and iron last week and folic acid was slightly high (noting to worry about) and iron was fine. I take a good multi vitamin daily and have a good diet so maybe that is why.

I will read into the links you attached and see if that sheds any light. I have also left a message for the society to call me back so will see what they advise.

Thanks again, much appreciated.

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Have you had your folate levels tested? Low folate can also cause large red cells.


Hi there,

The doc told me today that my levels were slightly higher than where they would expect them to be but nothing to worry about. Multi vitamin has 200% RDA folic acid and healthy diet.


I gave a copy of the whole "BCSH Cobalamin and Folate Guidelines" to my GPs.

fbirder has compiled a useful summary of quotes from mainly UK documents about B12. There's a link to his summary on his profile page and also a link in the third pinned post on this forum.

I take a copy of it to appts where B12 might be discussed. My experiences have led me to believe that some GPs are not well-informed about B12 so in my opinion it pays to read lots of B12 info and to know the current Uk b12 guidelines if in the UK.

"I was told I had depression. ME, Chronic Fatigue and then was basically told it was all in my head "

You have my sympathy, I had very similar experiences. There seem to be so many on this forum who at some point get diagnosed with ME/CFS/Fibro.

Another UK b12 website

Martyn Hooper has written other books about B12 and PA. Reading his book "Living with PA" made me cry with recognition, it was like reading about myself in some of the case histories.

"Could it Be b12" also has lots of case histories.

"I definitely show signs of nuro problems and thats what worries me the most!"

Did you have neuro symptoms when you were first told you had PA, 4 years ago?

If yes, did you have loading doses every 2 days for as long as symptoms got better? This is the UK standard treatment for PA with neuro symptoms. Maintenance injections should then be every 2 months.

see page 8 BCSH Cobalamin and Folate Guidelines for this info which is based on BNF (british national formulary) Chapter 9 section 1.2

Has your GP seen this BMJ article?

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Fab, thanks!

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I am trying to find the BCSH Cobalamin and Folate Guidelines on line. I found a 40 page PDF from 1994. Is this the correct document?


No, it's from 2014. They are in our Pinned Posts:


There are lots of different reasons why people run out of go with B12 well before 3 months - many are to do with the fact that having get up and go isn't about the amounts of B12 in your blood but another possibility is that your kidneys are very good at removing B12 from your blood so the levels in your blood actually drop very quickly. Testing for B12 after supplementation starts doesn't mean much unless it shows up low levels - the continuing enlarged red blood cells could well be an indication that your B12 levels drop quite quickly. However, there may also be something going on at the cellular level in your bone marrow where red blood cells are produced meaning that you have high levels in blood but not enough available there - ie a functional deficiency. The other thing that would cause enlarged red blood cells would be a folate deficiency but if you have good folate levels that is unlikely.


I am going to show this to my GP on the 4th of Oct - thanks!


"and this one wants to test my B12 but my understanding was that would be pointless "

Think that somewhere in the BCSH Cobalamin Guidelines. it mentions that testing b12 levels after b12 supplementation has started is irrelevant. There are two useful quotes about this in fbirder's summary(link in third pinned post) under heading "Further testing of B12 levels"


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