PA

Can you still get tested for pa if you are taking vit b12 spray?

Thanks

[Sleepybunny]

Hi,

I have read that the Intrinsic factor Antibody (IFA) test can give false positive results if carried out close to having a B12 injection. I think doctors suggest leaving at least 48 hours and up to 2 weeks after a B12 injection before having an IFA test.

labtestsonline.org/understa...

I don't know how an IFA test might be affected by Vit B12 spray.

I am not medically trained.

[KimberinUS]

mayomedicallaboratories.com...

I wouldnt take any b12 prior to an intrensic factor test, not even a multivitamin.

[Gambit62 Administrator]

Chaca - is your question about being tested to see if B12 is a the cause of a B12 deficiency or about being tested to see if you are B12 deficient.

Supplementing with an oral spray is likely to affect both serum and active B12 tests for B12 deficiency and it's recommended that you refrain from supplementing for 3-6 months before getting tested.

IFA is the test for PA as the specific cause of B12 absorption problems. Its a problematic test and is prone to false negatives - 40-60% of the time so a negative result doesn't rule out PA as the cause of a B12 deficiency. It can also give false positives if done too close to B12 supplementation but the period that you need to stop for is much less than with tests to measure B12 levels. The exact length of time you need to stop depends on the assay method but as below varies from about 48 hours to about 10 days

[Hidden in reply to Gambit62]

Hello gambit62,

It’s for intrinsic factor, b12 dropped over 80% in a year and now down to 232. My daughter has been taking the b12 spray for a few days now. Blood is on tue. Thanks