Many people are interested in having allergy testing performed to diagnose the cause of their symptoms such as rashes, swelling, abdominal pain or runny nose and there are many companies which claim to be able to diagnose all of your allergies and intolerances.
Unfortunately, these companies are often misleading.
An allergy refers to specific signs and symptoms that occur when there is a reaction from the immune system to something which should be harmless, like milk or grass pollen.
Allergies can be broadly divided into
- IgE (immunoglobulin E – a type of immune cell) and
- Non IgE mediated allergies
Currently, tests have only been diagnosed to identify IgE mediated allergies.
There are only 3 validated ways of diagnosing these allergies;
- Skin prick testing
- Specific IgE blood testing
- Oral food challenges
All other methods which are advertised are not validated and are not supported by the British Society of Allergy and Clinical Immunology.
These tests are not scientific and will be unhelpful. You or your child may be told to unnecessarily restrict your diet based on testing.
This is dangerous as it can cause children to lose their tolerance to foods and allergy may then form. In addition, over-restrictive diets can lead to malnutrition and growth impairment.
What is an Intolerance
An intolerance is an adverse reaction to a substance without an underlying immune mechanism ie. it is not an allergy. Some forms of ‘intolerances’ can be diagnosed with a test, like lactose intolerance or coeliac disease.
However, many intolerances that occur are not well understood and the mechanism of the reaction is not known. No one test can possibly diagnose every intolerance when the mechanism involved for each reaction may well be different.
It is vital that any test is not done in isolation. The first part of any investigation should always be to take a clear, focused history to find out what the problems are and what reactions occur. This should be done by qualified professional to ensure serious conditions are not missed.
Allergy skin prick tests are performed in a safe, clinical setting
Allergy Skin Prick Test Procedure:
- The arm is rested on a pillow with the inner surface of the arm facing upwards.
- Abbreviations are written on the arm, so we know what we’re testing eg. P for Peanut.
- Small droplets of solution containing various allergens (substances we are testing) are applied to the arm.
- The bubbles of solution are ‘popped’ with a lancet – this feels a bit like you have been poked with a blunt pencil. No blood is drawn.
- The solution is wiped away and we wait for 15 minutes.
- After 15 minutes, the raised bump is measured, and we can then give you information about the likelihood of allergy.
- If we do not have a solution of the substance we wish to test; we will ask you to bring the food you are concerned about to clinic. We can then prick the substance and then prick the skin. Again, we wait 15 minutes and see if a raised bump has appeared.
If you can't attend a face to face appointment...
Try Our Allergy Solutions Home Testing Kit
For individuals who are not able to attend a face to face appointment and need an option to have remote allergy testing performed, we offer an IgE blood test that can be performed at home using a blood sample collected from a fingerprick.
We will provide full instructions for this to ensure it is carried out correctly. It can be performed on individuals of any age.
This is also something which we can perform in clinic if indepth allergy testing is required. For an example copy of the report that will be received, please click here. The Allergy Solutions test looks at 295 allergens.
Your will get a comprehensive report see an example report here – REPORT EXAMPLE
Oral Food Challenge- Safe Environment
Oral food challenges are performed in a hospital setting. These are usually done to show that someone has outgrown an allergy and are performed in a safe environment in case a reaction occurs.
This is performed for those with IgE mediated allergies when it looks like their allergy has resolved – we are usually guided by skin prick tests and IgE blood tests becoming negative.
Food challenges can be arranged privately for those 18 years and under. We can also refer those needing food challenges into the NHS service to consider this. Waiting times on the NHS for a food challenge are usually one year, depending on your area.
Skin Prick Testing- Get your answer in 15 minutes!
Blood Test - Specific IgE Testing
Sometimes allergy skin prick tests are not possible to carry out (for instance if someone cannot stop antihistamines) or additional information is needed from a blood test. In these circumstances, a small amount of blood can be sent off and the amount of IgE against each substance measured. A measurement of >0.35 is positive. Blood will either be taken at the time or can be arranged at a later date with a trained phlebotomist.
Blood test results take up to 7 days to be ready. Dr Helen will contact you with the results and to discuss next steps. After an initial consultation, we will not charge for the follow up 15 minute consultation needed to discuss tests which have been taken in clinic.
Some high street allergy testing centres may send blood samples for analysis but if they are testing IgG (immunoglobulin G) and not IgE, then these tests are not a recognised form of diagnosis.
Please ensure allergy testing is done by an expert with the knowledge to understand when tests are indicated, choose the correct one and analyse them correctly.
Be cautious of anyone claiming to be able to diagnose all allergies and intolerances.
A Note About Alternative Allergy Testing
Alternative allergy testing has no proven benefit in the diagnosis of food allergy and food intolerances. These tests may endanger patients.
An accurate diagnosis requires a detailed clinical assessment by a qualified health care professional with expertise in Allergy and may include relevant validated investigations such as specific IgE testing, skin prick testing and oral food challenge testing.
Allergy and intolerance testing using hair analysis, VEGA testing and applied kinesiology are not validated methods and are advised against by the British Society of Allergy.
Want to research more?
Click below for more information from Choosing Wisely and the British Society of Allergy and Clinical Immunology