Test for intrinsic factor antibodies - when to do?

[fireflymairi]

Quick questions, I hope!

My doctor has agreed to this test but said we should wait until after 4 weeks after a third monthly injection of b12.

I don't really see the point in waiting, because if it confirms a Pernicious Anemia diagnosis, that would hopefully mean I could start on more frequent loading injections to get me back up to speed quicker.

At the moment, I'm getting about a week's discernible benefit/improvement from the monthly injections.

Is there a point to waiting that I might be missing?

And how long should this test be done after the last b12 injection - can the injections skew the results or (as I suspect) would the antibody be there regardless of the amount of b12 in my system?

My serum b12 was 250 and my active b12 was 113, by the way.

[Gambit62 Administrator]

The test needs to be done at least 48 hours after an injection with the most modern techniques - the time interval can be 10 days possibly more for some earlier test methods so advise would be leave for 2 weeks.

The test for IFAB is rather insensitive and there is a high probability (40%-60%) of a false negative. So, a negative doesn't prove that you don't have PA.

This insenstivity means that you might have to do the test many times before getting a positive though.

Having a positive for PA shouldn't really affect the treatment which is generally the same whatever the absorption problem. However, different absorption problems may have other consequences so knowing the cause helps screen for monitoring of other consequences.

Please note that protocols for treatment vary between countries and can even vary from region to region within a country. I'm not sure that there is a common protocol in Australia but you could try asking your GP what protocol they are using and ask that they refer to the BCSH standards which can be found here

onlinelibrary.wiley.com/doi...

In Australia, injectable B12 is actually an over the counter medication that you can get at a pharmacy - though from posts in the past it would appear that pharmacists aren't always aware of thisl

[fireflymairi in reply to Gambit62]

Thanks so much for your reply! This is exactly the info I needed. I don’t think my doctor is very knowledgeable at all about B12 deficiency unfortunately, she seems to think it’s just related to being “tired”.

I’ve had to push for the testing so far. I’ll just keep pushing! I’ll ask about the protocol.

My mum has PA. I eat a diet high in meat and animals products, and my folate is very good. So I’m sure it must be PA.

I have sourced some methyl B12 from the UK and all the stuff I need to self inject, but am holding off until I get an actual diagnosis before starting. It’s my backup plan if she refuses to treat me appropriately. 😂

[Nackapan]

I think it's best done before b12 injections start.

I was told this and I had parietal cell antybody test on one room and went in to havd my first loading dose in the next .

I now know that test isn't used on its own for a diagnosis

It's possible to have a false positive IFAB if b12 levels high in the body.

As already stated the ' new' tests shouldbnt

be affected .

So perhaps g.p out of date or just wanting the best conditions for the test?

A slower approach has been discussed on here of weekly rather thsn every other day loading Not heard of monthly without loading first though.

Monthly maintenance tends to be cyanocobalamin

[Sleepybunny]

"I have sourced some methyl B12 from the UK "

Was it in powder form?

[fireflymairi in reply to Sleepybunny]

Yes it is in powder form, it's from Oxford Biosciences Ltd.

[Sleepybunny in reply to fireflymairi]

Personally I would be wary of any B12 where a vial is used multiple times due to risk of contamination.

[Gambit62 Administrator in reply to fireflymairi]

firflymairi - as per Foggyme's response below we don't recommend using a dried product that would have to be mixed with sterile saline unless you can ensure that this is being done in a sterile environment because of the risk of contamination.It can also be difficult to source sterile saline for injections as, like B12, it's a prescription only if supplied for medical use and you would really need to be using medical grade saline.

[Foggyme Administrator]

Fireflymairi

About the powdered methylcobalamin from Oxford Biosciences...

I bought some methylcobalamin from Oxford Biosciences a couple of years ago - and ended up not using it because I was concerned about storage and maintaining the sterile status of the injectable B12.

The Methylcobalamin crystals came in a screw top bottle which has to be opened to add sterile (injection grade) saline - this is a prescription only item in the UK. Once the bottle of methyl crystals and the sterile saline is opened and mixed, the sterile integrity of the (now fluid) B12 can no longer be guaranteed and is therefore potentially open to contamination.

More specially, you will be injecting a substance which is no longer sterile and therefore open to contamination. And the potential for contamination and bacterial growth is further increased every time the B12 bottle is handled / opened and a new injection drawn up.

Would I advise anybody to inject a substance that has to be stored after the sterile integrity has been broken and which no longer comes from a guaranteed sterile source - no. Absolutely not.

We always advise using single dose sterile medical grade ampoules of B12 for injection.

[fireflymairi in reply to Foggyme]

I managed to get injection grade saline but I definitely see your point.

I wish I’d have known this before ordering!

Would I be better off getting this?

Does that mean I’d need to do IM injections instead of subcutaneous?

B12

[Foggyme Administrator]

That looks okay - 1mg hydroxocobalamin in 1ml (fluid volume). Can be given IM or SC.

If you haven’t had a B12 injection before it’s important to get the first one done when emergency medical attention is immediately available (rare but possible anaphylactic shock reaction which could require full resuscitation measures - CPR).

Good luck.

[fireflymairi]

Ok cool, yeah looks the same as what I’ve had already? I’ve had two of these administered by my doctor.

B12