Intrinsic factor test reliability

[Parlay]

Would one of you very knowledgeable people please remind me why the anti parietal cell/intrinsic factor test isn’t to be relied upon please. I’m trying to prepare for tomorrow’s fight with GP. Thank you.

[fbirder]

The anti-GPC test is no longer recommended because too many people without PA do have these antibodies. Testing positive isn’t a guarantee that you do have PA. However, I believe it can act as a Bit of confirmatory evidence. If you have low B12, gastritis and are positive for GPC antibodies then you almost certainly have PA.

The anti-IF test is a very good indicator of PA if it gives a positive result. But about half of people with PA do not test positive. See the BCSH guidelines - onlinelibrary.wiley.com/doi...

[Gambit62 Administrator]

just to clarify on fbirder's - the problem with IFA test is that a negative is a very long way from ruling out PA as a cause of a B12 deficiency, because the test isn't very sensitive and gives high levels of false negatives.

If you get a positive though (unless you supplemented just before) its highly unlikely that you don't have PA.

[Nackapan in reply to Gambit62]

How long do you have to leave this ifa test after an injection to be accurate please

[fbirder in reply to Nackapan]

That depends on the antibody test. It used to be three months, then it changed to a couple of weeks. The latest test claims there is no interference at all, so no need to leave any gap. But you don't know which test will be used. So it's best to leave two weeks.

Note that the interference can result in a false positive.

[Nackapan in reply to fbirder]

Okay thanks. I'm on 2 weekly b12 Injections at present si perhaps will wait until a slightly longer gap to be sure.

[Sleepybunny]

Hi,

A few links that may be of interest

PA tests

Intrinsic Factor Antibody (IFA) test

labtestsonline.org/tests/in...

Parietal Cell Antibody (PCA) test

labtestsonline.org/tests/pa...

PCA is not recommended as a diagnostic test for PA in UK.

Both these tests can be unreliable.

It is still possible to have PA with a negative result in IFA or PCA test.

About 50% of people with PA test negative on IFA test.

About 10% of people with PA test negative on PCA test.

There may be more info on PAS website

PAS (Pernicious Anaemia Society)

Based in Wales, UK.

pernicious-anaemia-society....

PAS tel no 01656 769717 answerphone

PAS support groups in UK

pernicious-anaemia-society....

Blog post about how PAS can support PAS members seeking PA diagnosis

martynhooper.com/2017/06/24...

UK B12 documents

BSH Cobalamin and Folate Guidelines

b-s-h.org.uk/guidelines/gui... test is mentioned in above document.

Flowchart from BSH Cobalamin and Folate Guidelines

stichtingb12tekort.nl/weten...

Flowchart outlines process for diagnosing PA and Antibody Negative PA in UK

BMJ B12 article

bmj.com/content/349/bmj.g5226

Emphasises need to treat patients who are symptomatic even if their B12 level is within range.

BNF

bnf.nice.org.uk/drug/hydrox...

BNF guidance on treating b12 deficiency changed recently.

pernicious-anaemia-society....

BNF Children

bnfc.nice.org.uk/drug/hydro...

NICE CKS

cks.nice.org.uk/anaemia-b12...

B12 books I found useful

"What You Need to Know About Pernicious Anaemia and B12 Deficiency" by Martyn Hooper

Martyn Hooper is the chair of PAS (Pernicious Anaemia Society). Book does not show updated BNF info.

"Living with Pernicious Anaemia and Vitamin B12 Deficiency" by Martyn Hooper

Has several case studies.

"Could it Be B12?: An Epidemic of Misdiagnoses" by Sally Pacholok and JJ. Stuart (USA authors)

Very comprehensive with lots of case studies. There is also a paediatric version of this book "Could It Be B12? Paediatric Edition: What Every Parent Needs to Know".

I haven't read the next book but plan to..

"Vitamin B12 deficiency in Clinical Practice" (subtitle "Doctor, you gave me my life back!" by Dr Joseph Alexander "Chandy" Kayyalackakom and Hugo Minney PhD

Other B12 websites

B12 Deficiency Info website

b12deficiency.info/

B12 Awareness

b12awareness.org/

B12d.org holds support meetings near Durham, UK

b12d.org/event

Stichting B12 Tekort (Dutch website with English articles)

stichtingb12tekort.nl/weten...

I've written a more detailed reply with lots of B12 info in next link to another thread.

healthunlocked.com/pasoc/po...

I am not medically trained.

[Mammaelf]

Hi, I am actually totally confused. I have 217 B12 test results.

I believe I have B12 deficiency but I have no idea what tests to actually ask for.

All the symptoms are exactly what I am experiencing!

Reoccurring sore throat and tounge , especially.

They are looking at my immune system but I really don’t think it’s that.

My folate was low so they put me on 5 mg a day, over 7 months ago.

Can someone please tell me what tests I have to ask for as the GP just fobs me off.

[Sleepybunny in reply to Mammaelf]

Hi,

This link may be useful

b12deficiency.info/b12-test...

None of the tests eg serum B12, Active B12, MMA, Homocysteine are infallible.

"folate was low so they put me on 5 mg a day, over 7 months ago. "

Giving folate without also treating a co-existing B12 deficiency can lead to neurological problems.

7 months seems a long time time to be on 5mg a day. What are your folate levels like now?

See Management section in next link

patient.info/doctor/folate-...

If you're in UK, see BSH Cobalamin and Folate Guidelines link.

b-s-h.org.uk/guidelines/gui...

Have you been tested for PA (Pernicious Anaemia), Coeliac disease, H pylori infection plus there are other possible causes of B12 deficiency?

Risk Factors for PA and B12 Deficiency

pernicious-anaemia-society....

b12deficiency.info/what-are...

b12deficiency.info/who-is-a...

You might find it helpful to start your own thread on the forum as that way you'll get more replies.

Lots more B12 info in my responses on this thread below.

healthunlocked.com/pasoc/po...