What do my allergy blood test results mean

What do my allergy blood test results mean

Blood tests may be used instead of, or alongside, skin prick tests to assist diagnose common allergies.

A sample of your blood is removed and analysed for specific antibodies produced by your immune system in response to an allergen.


Elimination diet

If you own a suspected food allergy, you may be advised to avoid eating a specific food to see if your symptoms improve.

After a few weeks, you may then be asked to eat the food again to check if you own another reaction.

Do not attempt to do this yourself without discussing it with a qualified healthcare professional.


Key points

  1. Commonly used diagnostic methods for identifying allergy include skin prick and/or blood tests combined with a detailed patient history.

    Component resolved diagnostics is capable to provide more detailed and precise diagnostic information and is becoming more relevant in allergy clinics.

  2. Allergies encompass a wide range of conditions varying in prevalence.

    What do my allergy blood test results mean

    They are characterised as an unnecessary immune response to an innocuous substance (such as pollens, latex, or certain foods). When these substances cause an allergic reaction they are considered an allergen.

  3. The prevalence of allergy in the UK and other developed countries is increasing. The reasons for this are poorly understood but are thought to be linked to changes in human lifestyle that own altered our exposure to the diversity of microbes.
  4. Allergy immunotherapy or desensitisation can be used in some cases to eliminate a person’s allergy by reversing their immune response to the triggering allergen.

    What do my allergy blood test results mean


Challenge testing

In a few cases, a test called a food challenge may also be used to diagnose a food allergy.

During the test, you’re given the food you ponder you’re allergic to in gradually increasing amounts to see how you react under shut supervision.

This test is riskier than other forms of testing, as it could cause a severe reaction, but is the most precise way to diagnose food allergies.

What do my allergy blood test results mean

And challenge testing is always carried out in a clinic where a severe reaction can be treated if it does develop.


Patch tests

Patch tests are used to investigate a type of eczema known as contact dermatitis, which can be caused by your skin being exposed to an allergen.

A little quantity of the suspected allergen is added to special metal discs, which are then taped to your skin for 48 hours and monitored for a reaction.


Allergy testing kits

The use of commercial allergy-testing kits isn’t recommended.

These tests are often of a lower standard than those provided by the NHS or accredited private clinics, and are generally considered to be unreliable.

Allergy tests should be interpreted by a qualified professional who has detailed knowledge of your symptoms and medical history.

Sheet final reviewed: 22 November 2018
Next review due: 22 November 2021

This briefing is also available as a PDF

An allergy is an unnecessary immune response to an innocuous substance.

What do my allergy blood test results mean

Examples of common substances people are allergic to include pollens, dust mites, insect venom and food such as nuts or shellfish. Allergies can range in severity with the most extreme symptoms seen in anaphylaxis.

What do my allergy blood test results mean

Every year in the UK, the number of allergy cases increases, mainly in children. This briefing should assist illustrate how allergy develops and possible reasons for increasing prevalence.


Skin prick testing

Skin prick testing is one of the most common allergy tests.

It involves putting a drop of liquid onto your forearm that contains a substance you may be allergic to.

What do my allergy blood test results mean

The skin under the drop is then gently pricked.

If you’re allergic to the substance, an itchy, red bump will appear within 15 minutes.

Most people discover skin prick testing not particularly painful, but it can be a little uncomfortable.

What do my allergy blood test results mean

It’s also extremely safe.

Make certain you do not take antihistamines before the test, as they can interfere with the results.


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