Intrinsic factor antibody

[suzybear]

I'm posting on here as I been advised to. I've just been back to my GP because I had a blood test done the other week for intrinsic factor antibody. I had a result of 3.66 which I thought was positive but my GP just said it's negative ? I had the test done because my vitamins b12 is 211.

[Nackapan]

It's useful yo have a range ( on brackets on thd right . Also mrsurement used.

A serum b12 ?test

Labs all differ.

Despite all this .

Symptoms should dictate and be treated

Other things ruled out.

Diet discussed.

Medications looked at .

Any surgery ?

Also iron ferritin, folate ,vit D and s full bloods count hopefully done.

Always good to get copy of your results .

Especially if first b12 test

[Nic878]

Is the IFAB ab test more accurate than GPC ab do you know. Your post has just made me realise there's 2 tests. Also I agree thats a positive result

[Nackapan in reply to Nic878]

Ypu need to remove name snd doctor ect .

IFAB usually test given for PA .

About 50% with PA test positive.

I'm sorry I dont understand the result either .

Hopefully a scientist will explain.

You seem to only just be 'in range ' for B12 .

Havd you an earlier one to Compare ?

My husbands was 180....no symptoms snd rose with oral b12 .

Others are in range but have severe symptoms .

It's all borderline/ in range.

Only you can differentiate with your thyroid symptoms .

Mine a big clearer as no othef medical issues going on.

My first b12 was 106ng/l( 200-900)

Still Gps reluctant to accept 'that was all' that wax causing my symptoms .

A baselineof b12 when well useful .

I have no idea what level I was well at.

Never given an IFAB test.

So 'assumed ' PA though b12 treatment challenged time and time again.

To date nothing else found.

I go by symptoms

Your folate and ferritin are in range .

But if you have symptoms of low ferritin like hair loss. Palpitations ect ask about iron supplements. 7 was told ax symptoms yo keep it above 50.

Sits at 48 at present !

I wouldn't take any folate as In range until its decided whether you are treated for b12 as b12 must be supplemented first .

Hood mord help comes as tricky ax you well know

[FlipperTD in reply to Nic878]

Scientist, not medic.

IFAb is specific; if it's positive, it's PA. However, it's not sensitive, so around 50% of cases of PA don't have a positive IFAb.

GPC antibodies aren't anything like as specific. Often positive in PA, but positive in lots of other conditions.

As for 'Is a result of 3.66 positive?' 3.66 of what? There isn't an international standard for calibrating the assay; there are numerous different ways of detecting IFAb, and putting a number on the result without giving a reference range isn't helpful. Labs running the tests will typically participate in inter-laboratory trials, so at least it might show that one lab's 'positive' is equivalent to another's 'positive' but if they're assigning numbers to them, the numbers aren't comparable.

So, IFAb is more accurate in the sense that it doesn't produce false positives. GPC antibodies produce more positive results but that doesn't mean they're showing someone has PA.

Once upon a time, we had Schilling Tests, which were a far more reliable means for investigating patients who were suspected of B12 malabsorption, both IF-dependent, and IF-independent. The tests were considerably more involved, required the patient to attend hospital for the procedure, to swallow radioactive B12, then to collect urine for the following 24 hours and return it to the lab for analysis. Being scientists, we appreciated what was going on, but when the manufacturers withdrew the test materials for a variety of reasons, we had nowhere else to go. It was a good test, but not infallible. It was possible for the test to fail at various stages. Fortunately, we had the IFAb test, which was much better than nothing, but nowhere near as good as Schilling Tests.

That's where we are at present!

[Nackapan]

Ypu need to remove your name and doctor and surgery ASAP

[suzybear in reply to Nackapan]

How do I remove it ?

[Nackapan in reply to suzybear]

Press more . Then delete. Could repost blanking odd Gp name your name ect

[Technoid]

The form seems to clearly say that <=20 is a negative result and >=25 would be positive. Your result was 3.66 U/ml so thats not even close to positive that I can see. Not sure I understand the confusion.

However ~ 50% of those with PA will still test negative for IFAB so it's not a result that can be relied on to exclude PA. I hope your GP is aware of this, but often they are not.

[Nackapan in reply to Technoid]

Good you could see the dot .I think the results shoukd state positive or negative though despite explanation .

As receptionist seem to give results to patients

[suzybear in reply to Technoid]

I think I got confused because firstly I went to the GP after I had my blood results and she said Im in range and don't need treatment prescribed for b12. But said about the intrinsic factor antibody test. As soon as bloods came back for this I get a text from the surgery saying about recent blood tests that they are prescribing me b12 tablets so I thought that meant ifat was positive. And reading the result yes I was confused. I put it on a previous post that my result was 3.66 forgetting to put the range in detail and was told it's positive. I won't forget to put the reference range again . I might get confused sometimes with autism. Thank you for the info that sometimes the test will sometimes test negative . I will suggest this to my GP when I see them next and hope I have some improvement with my b12 prescriptionThanks Suzanne

[Technoid in reply to suzybear]

Excluding B12 deficiency is quite difficult. I had a serum B12 of 210, similar to yours, 2 years AFTER neurological symptoms started. It took many months of twice daily injections to recover and there is some minor residual nerve damage. So from my personal experience, reading many others experiences and reading many scientific papers on B12 testing, I don't regard a serum B12 test as being all that useful tbh. The confidence with which many medical personnel rely on it only shows me they have not read the case literature, the opinions of B12 treatment experts or the many, many anecdotal reports which throw this test's findings into question.

[purpleabc]

My Intrinsic factor antibody test came back positive confirming PA it said, It was 2.5 u/ml. This was in 2015 , the range then was 0.00-1.20u/ml. I know this changes over time.

[Nic878 in reply to purpleabc]

Thats what I thought I googled ranges but they seem different to the ones that lab is using

[Sleepybunny]

Hi,

In some areas of UK, result of IFA test is reported as either negative or positive with no ref range.

Testing for PA

pernicious-anaemia-society....

Thread I started about tests for PA and B12 deficiency

healthunlocked.com/pasoc/po...

A negative result in IFA test does not exclude possibility of PA.

Quote from NICE CKS B12 deficiency...

"Antibodies to IF are very specific for pernicious anaemia, however, they are present in only 50% to 70% of people with the condition."

cks.nice.org.uk/topics/anae...

NICE CKS B12 deficiency

cks.nice.org.uk/topics/anae...

NICE is developing new guidelines for B12 deficiency, to be published in 2024.

nice.org.uk/guidance/GID-NG...

nice.org.uk/guidance/indeve...

If you suspect PA, have you thought about joining PAS?

pernicious-anaemia-society....

Membership of PAS is separate to membership of this forum. It's open to people worldwide and you do not have to have a PA diagnosis to join.

PAS (Pernicious Anaemia Society)

Based in Wales, UK.

pernicious-anaemia-society....

There is a helpline number that PAS members can ring.

PAS website has useful leaflets and a page for health professionals.

Diagnostic flowchart from BSH Cobalamin and Folate Guidelines which mentions Antibody Negative PA.

Good one to show GPs.

stichtingb12tekort.nl/engli...

B12 Info.com is another useful B12 website

b12info.com/

Unhappy with treatment?

How to write letters to GP about B12 deficiency

b12deficiency.info/b12-writ...

One thing I urge UK forum members to do is to find the local B12 deficiency guidelines for their ICB (Integrated Care Board) or Health Board.

If you can't find them online or by searching forum threads here then best bet is to submit a FOI (Freedom of Information) request to ICB/Health board asking which b12 deficiency guidelines are used locally and for a copy of or link to them.

See blog post below if you want to know why I suggest finding local guidelines.

b12deficiency.info/gloucest...

Thread about Patient Safety, has useful links for those in UK having difficult health experiences with B12 deficiency

healthunlocked.com/pasoc/po...

There is a lot of other useful info in pinned post "Various B12D/PA resources".

Pinned posts are on right hand side of screen if on computer. You may need to scroll up or down to find them.

I'm not medically trained.