Food intolerance tests

We had our French bulldog´s exam for allergies by Amazon.
It was quite accurate and exceptionally extraordinary in narrowing down that Edmond was allergic / intolerant totally to: Chicken / Poultry in any format, Chicken by products & Chicken meal ..

It was done by Edmond´s hair strands.

Dr Xand van Tulleken checked out food intolerance tests in Dr Xand's Con or Cure on BBC1. His assistant took about 3 or 4 tests and they call came back with different results. So it seems they're a waste of time!

Series 3 is on iPlayer but unfortunately it was Series 2 Episode 14 so not available.
Dr Xand's con or Cure

My granddaughter had hers done privately, but I can’t remember what it was called - I will try and find out where.

I won't waste my money on the online test.

I think they're rubbish. I did one, it wasn't a cheap thing off Wowcher or whatever and it never picked up on my gluten sensitivity and milk allergy. I wasn't avoiding these things either.

I am doing the FODMAP diet atm. Firstly, I went to my GP and he carried out some blood tests for coeliac disease and deficiencies. He then said it was a good idea to try the FODMAP diet to work out if any particular groups of foods are the problem. It’s a highly researched diet.

I too would like to know, however o too have been told these online tests are indeed a complete waste of money!

When I saw an NHS dietitian, she told me those tests weren't worth the money as they weren't particularly accurate.

Grammaretto

All I know is you send a sample of your hair to a laboratory where they "test it" and tell you which of thousands of potential allergens you are sensitive to. There's a traffic light system. Red: must avoid. Yellow: go easy and green: good.
It costs about £40. I can't imagine it can be accurate but could confirm what you already know.

These tests are not accurate.
I wouldn't waste your money.

No, I haven't but a GP might suggest removing the suspected items from your diet for a few weeks then reintroducing them to see if you have a reaction.
Dairy intolerance can be checked with a breath or blood test, I think.

Suspected coeliac disease is checked with a blood test but, of course, you must not eliminate gluten from your diet beforehand.

All I know is you send a sample of your hair to a laboratory where they "test it" and tell you which of thousands of potential allergens you are sensitive to. There's a traffic light system. Red: must avoid. Yellow: go easy and green: good.
It costs about £40. I can't imagine it can be accurate but could confirm what you already know.

How do they work please?