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Pernicious Anaemia Society
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Have I missed a trick?! Intrinsic factor testing without gpc antibodies test

I had a rushed but good conversation with GP.

He says my b12 has been about 200 since 2015!! I didn’t even know it had been tested before. In December 2017 b12 was 175.

Since I have autoimmune thyroiditis I asked to be tested for PA. He agreed and ordered intrinsic factor antibodies test.

Is testing for gpc antibodies necessary in this case?

I know sometimes you can be positive for gpc but not IFa, but is this true the other way round? If I’m positive for IFa then surely gpc is irrelevant. If I’m negative for IFA then I could still be positive for gpc? Autoimmune gastritis?

He agreed to b12 injections, but if I have them done will this affect gpc antibody testing in future ?

Thanks in advance- I’m kicking myself for not clarifying with him but every time I kept mentioning gpc he kept nodding and repeating IFa back to me.

7 Replies

Hi Saya85 according to the N.I.C.E. guidelines:-

"Not checking for gastric anti-parietal cell antibodies

Anti-parietal cell antibody is found in 80% of people with pernicious anaemia, but also in 10% of people without it. However, it has a low specificity of about 50%, which is much lower than that of anti-intrinsic factor antibody [Andres et al, 2004]. If anti-parietal cell antibody is not present it is unlikely that the person has pernicious anaemia, but its presence is not diagnostic as it can occur in other conditions (for example atrophic gastritis) and older people (16% of normal women over 60 years of age) [Carmel, 1992; Hoffbrand et al, 2006]. As a result, it is no longer recommended as a diagnostic test for pernicious anaemia [Devalia et al, 2014]."

Click on the link, then on "Scenario: Management" and scroll down through "Assessment"


I am not a medically trained person but I've had P.A. (a form of B12 deficiency) for more than 45 years.

I wish you well

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Thanks! I was pretty sure it was something like that but wondered if IFA came back negative whether it was worth testing gpc as I might have atrophic gastritis that’s causing my absorption problem?

I will read the link you sent me, many thanks


Like Clive says, GPC antibody testing is no longer recommended as it gives too many false positives.

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Thank you! thats Put my mind to rest


Actually, it's a good sign that your doc isn't stuck with 20th century ideas about PA.

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In my opinion, you can be ifa negative and atrophic gastritis positive which means stomach acid is lowered which can cause numerous nutrient malabsorbtion issues. If you have atrophic gastritis it needs to be addressed.

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Thanks that’s what I was thinking- and as I am Hypothyroid that could be a likely cause. Will see what the ifa results are first and hopefully GP will test the other

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