IgG Tests Are A Waste of Money: House of Lords Committee Hears Evidence, Let's Hope That They Listen

I think that IgG tests may accurately measure IgG levels but I do not believe that there is scientific support to confirm the relevance of IgG levels in the diagnosis of food intolerance. I have stated this in several posts over the last few weeks (see list at foot of post).

Today, the House of Lords SubCommittee that is looking into allergy and allergic diseases in the UK heard Dr. Glenis Scadding, Consultant Allergist of the Royal Nose, Throat and Ear Hospital, state this in a far more succinct and elegant fashion. My draft transcript of the full exchange from today's meeting (audio recording: available for 28 days and thereafter in transcript form) follows but the highlights from the redoubtable Dr. Glenis Scadding are:

What I do dispute is that it is worth making any attempt to identify IgG antibodies. We all make IgG antibodies to food....I see no way in which this can be used to guide diet.

I don't think there's any point in spending money on IgG antibody tests. You're better off going to see a dietitian and using an exclusion diet followed by reintroduction. The IgG antibody tests are liable to leave patients on diets that are inadequate and patients often like to think they're improving. They carry on in the teeth of very little improvement and may end up malnourished.

I think [self-testing kits] should be banned.

My draft transcript of the relevant part of today's committee meeting is as follows. I will amend this when a better recording is available or as an authorised transcript is available. I have identified the speakers where practical: CM indicates that a subcommittee member is speaking. Any mistakes or emphases in the transcript are mine.

Start transcript of oral session, 15 March 2007.

At around 1:23 the committee members discuss the YorkTest consumer satisfaction survey paper commissioned by Allergy UK and irritable bowel syndrome. Ms McManus of Allergy UK praises the value of the Hardman and Hart study and its implications for chronic illness.

Dr. Scadding: It's well known that irritable bowel syndrome can respond to dietary exclusion; I have no dispute with that. What I do dispute is that it is worth making any attempt to identify IgG antibodies. We all make IgG antibodies to food. Pam Ewan will tell you that 100% of the population she studies has IgG antibodies to egg and I see no way in which this can be used to guide diet.

In the Gut paper, which is the best paper produced, the sham group did not avoid dairy or wheat which are the two major problems with IBS patients and therefore it's not surprising that at the end of the survey there was a 10% difference. In that paper you needed, the number needed to treat was 9, whereas if you do an exclusion diet the number needed to treat is somewhere between 1 and 2.5.

So, I don't think there's any point in spending money on IgG antibody tests. You're better off going to see a dietitian and using an exclusion diet followed by reintroduction.

The IgG antibody tests are liable to leave patients on diets that are inadequate and patients often like to think they're improving. They carry on in the teeth of very little improvement and may end up malnourished.

CM: These [are] self-testing kits you're referring to.

Dr. Scadding: No. These are the York Laboratories' blood tests.

CM: Tell us what you think about self-testing kits and whether they should be-are they sufficiently-regulated?

Dr. Scadding: They should be banned.

[Laughter.]

Dr. Scadding: I'm very sorry...But...For example, I saw a child this morning before coming here and she had...We did skin tests that are well recognised and she had skin tests to house dust mite and also to tree pollens. Two kinds of tree pollen. She has absolutely no symptoms referable to the tree pollen whatsoever. She does not have Spring Hayfever. She has good symptoms related to the house dust mite, so I treated her with house dust mite avoidance and anti-allergy therapy.

If she had got a kit, then she would have felt that she was tree pollen allergic as
well and something had to happen about that. She has sensitisation but not clinical disease. And if you do a test, only about half the people with that positive test will have clinical disease.

So, you can not have self-testing kits: they're going to lead to mis-diagnosis, mis-allergen avoidance. You need both the test and a detailed history taken by somebody who has some experience of allergy history taking and interpretation of tests.

CM: But because the number of experts is so few and far between...It's inevitable

Dr. Scadding: Absolutely right...

CM: ...it's inevitable that you are going to be using tests.

Dr. Scadding: People are training-a lot of Primary Care nurses are being trained in doing skin prick tests and interpreting them, in places like the Respiratory Training Centre at The Athaneum in Warwick. And I think that may be a way forward.

CM: [Calling on Dr. Mills]

Dr. Mills: I'd just like to endorse what Glenis had said and I think actually for food allergy it's even worse. And that there are a lot of people who will have apparently been sensitised to foods like wheat but actually don't have any symptoms. And that can be really problematic when people eliminate important food groups from their diet.

CM?: What about the issue of inflammatory bowel disease that we heard about in the last evidence session.

Dr. Mills: What? You mean in terms of the IgG or the...

CM: Yes.

Dr. Mills: It's not particularly my area of expertise. But I think that it's a symptom and that people do benefit from dietary interventions. But the link at a molecular basis between IgG and irritable bowel syndrome is not apparent. And we make these antibodies to our food protein as part of our normal functioning.

CM: Ms McManus? This was a study that, if I'm right, your organisation commissioned. I just wondered if you had anything that you want to add to what's been said.

Ms McManus of Allergy UK: I think the main thing that I've got to say is as we were saying. You know... It's a lack of other places to send these people to. Err, we would give the YorkTest purely because it's the only one that has undergone trials-particularly for IBS and that's what we would say, that we would [be] happy to endorse it for, would be for those kind of symptoms. Eh, but, you know, we wouldn't recommend any other test.

End transcript.

I have to say that I am surprised to hear Ms McManus say that, as Muriel Simmons endorsement of YorkTest tests has been used considerably more liberally than solely in the promotion of IgG tests for IBS. I have said repeatedly that if Allergy UK limit their endorsement of YorkTest food intolerance tests to irritable bowel syndrome then they should state this unequivocally.

Allergy UK might consider whether it is premature at best to discuss the purported value of food intolerance testing in the treatment of chronic illnesses. They have said, repeatedly, that the people who contact them rely upon them for a good quality of advice and place their trust in them. It now seems as if some of the proxy trust that people have been asked to place on the value of IgG tests for food intolerance has been misplaced. Similarly, questions may need to be asked about Allergy UK's collaboration and endorsement of an IgE test (the YorkTest Allergy UK MAST (multi allergy screening test)) that does not mandate the involvement of a suitably qualified professional in the interpretation and implementation of the results.

If Allergy UK is truly recommending YorkTest faute de mieux and for want of anywhere else to make referrals then I have some suggestions:

• coach the enquirer to advocate for themselves or someone else when approaching a GP
• if a GP is unable/unwilling to make a referral to an NHS Allergy Clinic, then advise the enquirer to consider a private referral to a Clinical Allergy specialist. Even in London, for the cost of a YorkTest 113 foodSCAN test for intolerances, it is possible to purchase:
  • a consultation and tests at a well-regarded allergy clinic
  • a consultation with a leading consultant and researcher plus several tests
  • a consultation with a leading consultant and researcher, but tests would an additional cost
  • outside London, I would expect people might be able to have a consultation with an expert and comprehensive and relevant testing
• several consultations with a dietitian (NB, appropriately qualified dietitian, not a nutritionist) who can guide and support the enquirer through an elimination diet.

If an enquirer suspects that they might have a mix of allergies and intolerances and requires both the YorkTest Allergy UK MAST (multi allergy screening test) and the 113 foodSCAN test, then the price comparison with the cost of seeing a relevantly qualified and experienced Clinical Allergy Consultant is even more favourable. Any of these suggestions are more likely to result in a more relevant outcome for the enquirer than an IgG test.

Related posts:
Food intolerance testing and migraine
Truthiness and referenciness make the case for IgG food intolerance tests
More allergy and intolerance testing nonsense: part 1
More allergy and intolerance testing nonsense: part 2
Quote Mining and Misrepresentation: Poor Ways to Claim Clinical Validation or Sound Science
What is the Significance of IgG Antibodies and Testing?
Why IgG Testing for Food Intolerance Is Not As Simple As ABC or Doh Ray Mi