Pernicious Anaemia Society
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Intrinsic Factor test can it be wrong?

Hi, I had my Vit B12 Result say 299 in 2015. It was in range but on bottom . My dr put me on Vit B12 Sublingual for 2 weeks and next visit she gave me an injection of B12, she then sent me over to lab and had me get Intrinsic Factor and Gastric Partial tst.

The test said Positive for IF test, and Equivical for GPA test. She then said I had Pernicious Anemia and gave me a total of 47 injections over 8 months. My levels went quickly up to 2000. I never felt any better from shots, I would be in bed feeling sick, and started getting pins and needles in my feet and legs, and was shaking from shots, and felt very anxious. I found a new Dr. she said she didn’t think I had PA and stopped shots. She ran Intrinsic Factor test result was 0.9 no range was on test. Plus I had so much B12 in me . She also ran GP cell test it was 30.9 no range on test. Also she did MMA test and Homeocistine test which werein range. The first Dr never did Homeocistine or MMA test at time she did IF test. Im feeling awful as my short term memory and now depression no energy, My last Vit B12 levels were 512 in September.

Im taking Sublingual B12 and it has been keeping around 500. My vitD is 38. I also have Hashimotos thyroid for 20 years. And have been on Lexapro for over 15 years. The 1st Dr had put me on Ativan because of shaking. Itapered off that and have been off for 8 months. I can’t figure out if these Test were all wrong or if I have PA. My symptoms are fatigue, short term memory, shaking, no appetite, diahrea, and depression which I neber had before the shots.,or the Ativan. I do have Colegnus Colitis which can cause Diahrea. Plus after being on all these meds my Thyroid levels are off and I have high RT3. The Thyroid meds have been changed 4 x this Summer, still struggling.

Im wondering what any of you think about the Pernicious Anemia...can all these test be wrong under the circumstances of way they were done. Could I actually have PA and maybe Ii just needed more shots? Or could the shots 47 of them made me this sick? Help? Thx

2 Replies

Hi Oberley It is also important that your Folate level is monitored as this is essential to process the B12 you've been taking.

There is a complex interaction between folic acid, vitamin B12 and iron. A deficiency of one may be "masked" by excess of another so the three must always be in balance.

Symptoms of a folate deficiency can include:

symptoms related to anaemia

reduced sense of taste


numbness and tingling in the feet and hands

muscle weakness


Folic acid works closely with vitamin B12 in making red blood cells and helps iron function properly in the body acid works closely with vitamin B12 in making red blood cells and helps iron function properly in the body.

The IFA test is unreliable in that it gives false negatives in people with PA half the time. So a negative result doesn't mean that you don't have PA. However, a positive result is a sure-fire, 95% certain indicator of PA.

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

I wish you well


recent supplementation and an injection will give false positive results on the IFA test - how long you need to leave it between a shot and the test varies depending on the exact test method but the minimum time would be 24-48 hours - and for many other methods its nearer 10-14 days.

Done outside these periods IFA test is notoriously prone to false negatives - 40-60% of the time depending on the assay method - so a negative result is a long way from being conclusive evidence that you don't have PA.

If you have hashi's there's a good chance that you will also develop PA - rates in studies tend to vary between 10-40%.

Article on thyrogastric syndrome for you

there's such an overlap between thyroid and PA symptoms that I'd be inclined to suggest focusing on getting the thyroid under control.

MMA and homocysteine being in range is also pointing away from B12 being the issue (though there is some debate around the margins of medical research as to exactly how conclusive these measures are in ruling out a B12 deficiency at the cell level - ie I have seen papers where questionmarks have been raised)


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