Intrinsic Factor Reference Ranges

[miravet]

Hi, I wonder if anyone can shed some light on these reference ranges for intrinsic factor.

The first one was done 2013, when I was convinced I had PA.

The second one was done in June this year by Medichecks.

The third one was done by my GP on the 29th of August. I have no idea why she ordered it as I SI every day and she knows it, I tried to tell her the result would be skewed but she disagreed.

The last one has come back as 'negative' , I have to see her on the 17th of this month, I am seriously hoping she doesn't think I am somehow cured.

What is confusing me is the reference range differences. Why are they all so different.

[miravet]

Oh sorry, I thought I could put more than one picture , the second test was the medicheck one, the result was

6.64 AU/ml Range < 1.2 so clearly positive

The second one was done last month

4AU ( range 0.00 - 25)

[FlipperTD in reply to miravet]

IFAb methods used in labs vary considerably, and to add further complexity there isn't an accepted international standard either. Method sensitivities vary a great deal and 'Reference Ranges' are really not very helpful. Sorry.

[fbirder]

Different assay types on different equipment - probably.

[miravet]

Hi, thank you for your replies, amongst the recent blood tests the GP did, they included a ferritin one, I have read a lot about co-factors, my ferritin level was 34 ug/L Range ( 23.00 - 300) , I am thinking that this may be too low.

[fbirder in reply to miravet]

There is no reason to think that a level 150% of the bottom end of normal is too low.

B12 is unusual in that there is a wide overlap between people who are symptomatic, but above the bottom end of normal, and those who are asymptomatic, but below the bottom end of normal. There is a very wide 'grey area'.

Other biochemical measurements are much more clear-cut. So that a value above the bottom of normal is fairly sure of not causing problems.

[miravet in reply to fbirder]

I have a lot of 'unusual' going on with me, I have got PA,(IF results above) but I also have an incredibly high active B12 reading, my test for active B12 was done at the same time as the IF one, my result was totally independent of any B12 supplements, I didn't start supplementing until after I got the IF and Active B12 result.

My active B12 was >300 pmol/L Range: ( 37.5 - 188)

Clearly not reaching the right place as I was terribly symptomatic prior to SI , I also can't go 24 hours without some of the major symptoms coming back.

My son is a mature student in his final year of a Human Health and Nutrition degree ( set to get a first), he has had a good look at what is going on with me and also had a word with his Prof, the consensus seems to be an issue with Transcobalamin 2.

I think my son is going to do his dissertation on this issue, he was going to do Vit D and it's effect on depression, but is now considering changing.

I have an appointment with my GP on the 17th, he is going to put together a report on what he thinks is going on

[fbirder in reply to miravet]

Depending on the test they use for IF antibodies, very high levels of B12 can give a false positive.

[miravet in reply to fbirder]

Hi, so the first IF test done by Medichecks prior to any supplementation but considering my high Active B12 could be a false positive, but the second test done by the NHS, AFTER I have injected daily for approx 1 month with no break prior to my blood being drawn , was done by a different method whereby my high circulating B12 did not interfere with the test and came back negative ?

[fbirder in reply to miravet]

That is possible. It's also possible that the NHS test was a false negative and you do have IF antibodies.

Sorry, not much help.

[miravet in reply to fbirder]

Hi thanks for the reply, I think as I already have Hashimotos and my father and grandmother both had pernicious anaemia, I think a positive diagnosis is more than likely.

[miravet]

Hi, sorry me again, just trying to get to the bottom of why I seem to need to inject every day or 90% of my symptoms return within 24 hours.

First I have found out that Medichecks use the ELISA test for IF antibodies.

Also I am going to ask my GP to do a MMA test and homocysteine one, can anyone tell me if either of these tests are likely to be skewed if I am injecting daily.