IFAB test

[UpsyDaisy2]

When should the IFAB test be done please? I've read somewhere that it should be before starting treatment? Mine was immediately after my 5th losing dose. Could this explain why it was negative? Or is it not that simple!

[wedgewood]

You need ,at the very least , to be 2 weeks clear of a b12 injection before having the IFAB test . That you took the test so soon after the B12 injection is not necessarily the reason that you tested negative . Roughly 50 % of Pernicious Anaemia patients test negative to the IFAB test . Our founder Martyn Hooper needed to test 3 times before he got a positive test . Trouble is that many doctors do not know about or even acknowledge this fact . ……

[Nackapan]

Yes it's best to do before b12 injections start .I thought the concern was s false positive if alot of b12 in your blood stream.

It's worth having another after b12 loading doses before your first maintenance injection.

There are many absorbtion issues for B12.

[Orchard33]

Mine was done 3 months after the loading doses and before the first 12 weekly. It was negative but my GP still treated as if PA because my initial B12 count was so low. Half IFABs are inaccurate.

[UpsyDaisy2 in reply to Orchard33]

So have you ever had a formal diagnosis of PA or just being treated as such? I've persuaded my GP to give more B12 and he's happy to continue if they make me feel better. 😀 But I worry that there is no formal diagnosis.

[Orchard33 in reply to UpsyDaisy2]

I don't have a formal diagnosis. It is the illness that dare not speak its name at my surgery. I use the term Pernicious Anaemia whenever I can introduce it in a conversation. I'm invariably met with something resembling a brick wall. It is a weird experience not unrelated to gaslighting! Your GP sounds refreshingly flexible.

[FlipperTD in reply to Orchard33]

Scientist, not medic.

I take issue at the 'half IFAbs are inaccurate'. It's not that simple. Half of PA patients don't test positive. Some folks don't produce IFAb that we can detect. If it's not there, then we can't detect it.

The tests in use are quite precise. If we get a positive result and a magic number generated, then the test, if done well, will tend to produce very much the same number on repeating on the same sample.

I appreciate it's infuriating that we don't have a magic test! We did, with Schilling Tests, but they've gone.

Sorry to be pedantic!

[Orchard33 in reply to FlipperTD]

I like accuracy.

[FlipperTD in reply to Orchard33]

Thanks for your response. I love accuracy too; my background taught me that. Without precision, we can't have accuracy. The IFAb test is [when performed well, by experts] is precise. In the UK, we have Government-sponsored National External Quality Assurance Schemes, including one for IFAb. This gives us a good degree of confidence that all labs participating generate reliable results, even when using different methods. The test I used gave the same result on the same sample, hence precise. It's a fact of life that not all patients with PA have demonstrable IFAbs.

Pernicious Anaemia is a tricky one to handle; it's a clinical diagnosis, and very much a diagnosis of exclusion. Exclude all the other causes, and it's what you're left with.

[Nackapan in reply to FlipperTD]

Yes I understand your view point .It's very hard whe you are trying yo get treatment without a formal diagnosis.

I agree clinical response and symptoms of most importance .

Unfortunately alot of Gps only act on blood test results alone.

My very low serum B12 when nothing else found started mh treatment

I was not given the IFAB test .

Wasn't evan aware of the test at the appropriate time.

Then all patients receiving B12 Injections were sent a letter by the surgery .

It had a blood form for IFAB and b12 / folate.

It stated very clearly if your b12 blood levels were 'normal '

And IFAB negative your B12 Injections would stop.

Also went on to say high B12 levels were dangerous!

Not a nice predicament to be in.

Nothing else found to treat and by then regular prescribed B12 injections were giving a small percentage of my life back.

I refused the blood test .

My prescription of B12 continued.

[FlipperTD in reply to Nackapan]

Thanks for your response. We really are in a quandary here, because once upon a time we had a test that could detect absorption of B12 with and without IF; the DiCoPac [Schilling] test. It was complicated to administer, and even then, it relied on the patient being B12-replete when they came for the test. [It's no longer available for technical reasons.] The the gut doesn't absorb B12 effectively when you are B12 deficient, so performing a Schilling Test when deficient would under-read the absorption result, as the radiolabelled B12 would not absorb effectively. Likewise, the test required us to administer a B12 injection at the same time, to saturate the transcobalamins before the radioactive B12 was administered. Otherwise the body would absorb, store and utilise the radiolabelled B12.

It is unfortunate that there is a great deal of misunderstanding out there, but the Schilling Tests were the only ones we could use to give a laboratory diagnosis. The IFAb test, which is considerably simpler and cheaper, only give us the answer we seek half the time in patients with PA. That's unsatisfactory, I admit, but IFAb negative cases of PA are just that; PA without demonstrable IFAb. It's may be worth repeating the test in those cases, and I have seen some cases where the positivity increases as time progresses, but it's probably not going to make a huge difference to the overall percentages.

I realise I'll attract all sorts of attention with my next statement, but it's believed that there are more folks on regular B12 injections than there are cases of PA. There. I've said it again! That is not, however, a reason to contact all patients on B12 injections in the manner you describe. That to me sounds rather more like a clinical trial, [probably not registered as such], and an attempt to reduce the numbers of B12 injections, to reduce the costs and the workload.

The 'high levels are dangerous' statement is unlikely to have been based on clinical evidence. If the level was normal, when on injections, then the injections are being given correctly. What else would they expect?

You were right to stick to your guns. We're proud of you!

Good luck and stay healthy.

[Myoldcat]

I think this flow chart is useful for those of us who have the "All your other tests are normal" non positive IFAB version of PA... we're the yellow box! So we DO exist!

Flow chart of B12 deficiency diagnosis

[topazrat]

I had one done before treatment and one done while I was injecting weekly. Both were positive.

[Nackapan in reply to topazrat]

Why was a second done ?

[topazrat in reply to Nackapan]

Your guess is as good as mine! I didn't know he was doing it, or would have told him that it was a waste of time! The practice owner wasn't too happy about him doing it, said it was a waste of time and money.

Maybe he was hoping it was going to be negative second time round and they wouldn't have to give me jabs. Who knows what his logic was.

[Nackapan in reply to topazrat]

That's awful without telling you.I didn't realise B12 is done with Folate.

Sensible at the start but not needed once on B12!

.

As id started 400mcg of folic acid I wanted to know the level .

Folate rose as quickly as B12 from 5 to above 26 i know I can absorb that supplement by tablet !

Fortunately the G.p just said oh that's very high about the 2000 B12 level

I just replied

" it should be shouldn't it ?"

She moved on.

Glad two positive IFAB tests .make

sure you have a paper copy !!

I wasnt given one IFAB test let alone two!

I think the chosen G.p wise ther given the practices new policies