Confused again 😕

[Popcorn12345]

How do you know if your intrinsic factor antibody blood test is good or bad?

[Narwhal10]

Hi Popcorn12345,

The Intrinsic Factor test is only 50 % effective. So, lots of False negatives meaning you can have the antibodies but the test will not pick up the result.

So, usually the laboratory reports a Positive or Negative - Yes or No. However, I have seen some people report numbers. I do NOT know the ranges. So, using 2 examples.

Test Result for The Count of Monte Cristo

2.2 mg/L < 4.8 mg/L

[ So, 2.2 is less than 4.8. So, it is NEGATIVE. ]

————————————————————————————————————————

Test Result for Rhett Butler

5.9 mg/L < 4.8 mg/L

[ So, 5.9 is greater than 4.8. So, it is POSITIVE.]

[Popcorn12345 in reply to Narwhal10]

They ran the partial cell test too. But I don't know how to understand all the results

[topazrat]

The ranges seem to vary by area, which doesn't help. For example mine was:

Intrinsic factor antibody level 29.4 u/mL [0 - 6.1]

But I've seen others where its positive under a much lower number, so I feel your confusion.

[Rexz]

Simply, if IFaB show positive then the test is good as the test is very specific to PA. However, if the test shows negative then it is neither good nor bad just indeterminate. A negative does not mean you do not have PA or IFaB.

[Popcorn12345]

This is just ridiculous. How u supposed to figure it out then

[FlipperTD in reply to Popcorn12345]

Scientist, not medic.

I feel your frustration. Then again, that's why we have doctors to interpret the results for us. Some are better than others. Some are much better at it than others!

The standard advice is 'Treat the patient, not the numbers', so treat the symptoms.

The frustration of IFAb only being positive in about 50% of cases of PA is a nuisance, but it doesn't make it a 'flaky' test. Just that some patients do not demonstrate binding or blocking antibodies to Intrinsic Factor. At least the IFAb test gives a positive result in 50% of PA cases. I realise that if you're one of the 50% of 'IFAb negative PA patients' that doesn't help you. Once upon a time we had the Schilling Tests, but those days are gone for a variety of reasons. It was a superb test. It took a long time to perform. It only worked on patients who were B12-replete. Very expensive to perform, and with lots of opportunities for it to fail if done badly, but it was better than the IFAb test in terms of accuracy. However, it's possible to do hundreds of IFAb tests compared to one or two Schilling Tests. The frustrating thing is 'we are where we are'.

[Popcorn12345]

Thank you for the response. I can't get a doctor to take me seriously. I guess for now I will have to just supplement and hope for the best.