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Pernicious Anaemia Society
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Hi guys,

Looking for a bit of advice. My b12 level was 58 so my doctor is starting me on the injections, 5 over a two week period. He also said they did a test which came back saying that I CAN absorb b12 but I'm just not. He's not sure what's causing it and said he hasn't come across anyone with such low b12. He's also sending me for further blood tests because my phosphate levels were low and he wants this to be rechecked. He's asked me to do a stool sample and then to see him when the results come back but he thinks I'm going to need a colonoscopy also. Is this PA? Or just a b12 deficiency, or something else? My other symptoms are; tiredness, stomach pain after eating and diarrhoea for about 5/6 months. Any advice would be appreciated!

10 Replies

There is, as far as I know, only one test that can tell is you can absorb B12 - the Schilling test. But that's not carried out anymore because it needs B12 with radioactive cobalt - and nobody makes that any more.

What your doctor probably means is that they did a test for anti-IF (Intrinsic Factor) antibodies and it was negative. The anti-IFAB test is a good indicator of Pernicious Anaemia (and the inability to absorb B12) if it's positive. However, about 50% of people with PA give a negative test result - so it cannot be used to rule out PA.

If there are no other obvious causes for the low B12 (if you were vegan, had gut surgery, abused nitrous oxide, took certain drugs like metformin or PPIs) then the most likely cause is antibody-negative PA.

But it doesn't matter. In the absence of any proven temporary cause the treatment would be the same - lifelong injections of B12.

A colonoscopy won't do much to figure out low B12 (dunno about low phosphate). A gastroscopy (same sort of thing, but from the other end) would show if you had gastric atrophy - the leading cause of Pernicious Anaemia.


I too thought they had stopped but I came across this a while back and wondered whether they are still actually doing the Schilling Test in Poole.



Fascinating. I wonder if Martyn and the PAS are aware of this? PAS-admin ???


I didn't know, but as you know I'm not in touch with British things ;) I'll ask Martyn. But the Shilling test is also not 100%, ..Ralph Carmel:

" the Schilling test was never popular with patients or some

clinicians. It is unwieldy and requires an overnight fast, ingestion of (modestly) radioactive cobalamin, a 24-h collection of urine, a cobalamin injection, 2 trips to the laboratory, and, if the result is abnormal, repetition of the entire procedure with a dose of IF. Like all tests, it has its limitations; it requires normal renal function and complete urine collection and occasionally produces uninterpretable results"


Answer: "Probably old text and they didn't take it down - there is no radioactive B12 in the world"


Afraid I suspect that the information has somehow been retained on the wbesite even these many years after the actual substance became unavailable. At least, that is how I interpreted the Poole page when I saw it a few months ago.

It would be good to know for sure - rather than relying on my assumptions!

1 like

Check for Coeliac and folate


The symptoms of PA are the symptoms of the B12 deficiency that it causes by stopping/hindering the absorption of B12

As others have said - test for IF only rules out one possible absorption problem. Unless it can be proven that diet is the cause then it is an absorption problem - aside from PA there is general lowering of stomach acidity as you get older, genetic abnormalities affecting the ileum, gastric surgery affecting the ileum (which would include gastric band), h pilori infection, tapeworms (more common in scandinavian countries where they eat a lot of raw fish) and some liver problems.

Some of those problems can be dealt with - eg the tapeworms - but most of the others can't so treatment would be same as for PA.

The normal range is a statistical average - so whilst most people will be okay some won't even though there levels are normal ... and there will also be some people who will be okay even though there levels are below normal, so may be that you are one of those people so your levels got really low before you started to become symptomatic ...

symptoms tend to snowball when your levels get really low with an absorption problem - and it can take decades for an absorption problem to finally become a detectable/clinically obvious deficiency because under normal circumstances the body stores quite a lot of B12 in liver and releases it into the ileum for reabsorption but if there is a problem with absorption in the ileum then its like having a hole in a bucket ... and gradually you become more and more deficient.

really suggest that you point your GP at the PAS website are for medical practioners.



Helicobacter is a tough little animal that eats up iron an B12. It is located in the stomach and very very hard to get rid off. It also produces diarrea.

Check it up in the stool analysis.



I've assumed you're in the UK.

I hope your GP has read the "BCSH Cobalamin and Folate guidelines". I read the whole document then I gave my Gps a copy...

Page 29 is a diagnosis flowchart that shows the recommended process a doctor should follow with someone they suspect has b12 deficiency.

page 8 gives details of UK B12 treatment.

I also gave Gps a copy of Martyn hooper's book "What You Need to Know About Pernicious Anaemia and Vitamin B12 Deficiency"

Martyn is the chair of the PAS (Pernicious Anaemia Society).



"He also said they did a test which came back saying that I CAN absorb b12 but I'm just not"

A negative result in the IFA(intrinsic Factor Antibody) test does not rule out PA. The BCSH Cobalamin and Folate Guidelines mention Antibody negative PA on page 29.

Causes of b12 deficiency


Other books

"Could It Be b12" by Sally Pacholok and JJ. Stuart. very comprehensive book about b12 deficiency.

"5 over a two week period."

Do you have any neuro symptoms?

pernicious-anaemia-society.... click on Symptoms Checklist.


In the UK, I think someone with B12 deficiency without neuro symptoms is supposed to get 6 loading doses not 5 then injections every 3 months. See page 8 BCSH Cobalamin Guidelines

A person with B12 deficiency who has neuro symptoms should get loading doses every other day for as long as their symptoms get better, after this they should get injections every 2 months.

Untreated or inadequately treated B12 deficiency may lead to permanent neurological damage.

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




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