Everything You Need to Know About Allergy Testing

If you’ve been experiencing symptoms like sneezing, itchy eyes, or skin rashes and suspect you might have an allergy, allergy testing can provide clarity. Whether you’re dealing with seasonal hay fever, food allergies, or other sensitivities, knowing what triggers your symptoms is the first step in managing them. This guide will explore how you can get an allergy test, the types available in the UK and how long they take.

How Can I Get an Allergy Test in the UK?

Getting an allergy test in the UK is relatively straightforward, with several options available depending on your needs. Here are the main pathways:

GP Referral

If you suspect an allergy, your first step should be to visit your GP. Your doctor will assess your symptoms and may recommend allergy testing, which could include blood tests or skin prick tests. A referral to a specialist may be necessary for more complex cases, such as those involving multiple allergies.

Private Clinics

Many private healthcare providers in the UK offer allergy testing without the need for a GP referral. These tests are typically quicker and may offer more comprehensive options than those available through the NHS. Examples include the skin allergy test and blood tests that look for specific allergens, you can read about them on Nuffield Health. 

At-Home Allergy Tests

If you prefer to take a more hands-off approach, several at-home allergy testing kits are available. These generally require a blood sample or a small prick on your finger, which is then sent to a lab for analysis.

Types of Allergy Tests Available

There are different types of allergy tests, each suited to different purposes. Here are the most common options:

Skin Prick Test (SPT)

A skin prick test is one of the most common allergy tests. A small amount of the suspected allergen is placed on your skin, usually on your forearm or back, and then a tiny needle is used to prick the skin so that the allergen can enter the body. If you're allergic to the substance, you'll develop a small raised bump at the site.

• Time: Results are usually visible within 15–20 minutes.
• Common allergens tested: Pollen, pet dander, dust mites, and certain foods.

Blood Test (RAST or ImmunoCAP Test)

Blood tests measure the levels of specific antibodies (IgE) that your body produces when exposed to allergens. These tests are useful when skin tests are not an option or when allergies are suspected to be more complex.

• Time: Results take several days to come back from the laboratory.
• Common allergens tested: Pollen, foods, mould, animal dander, and insect venom.

Patch Test

Patch tests are used to diagnose delayed allergic reactions, particularly for substances that cause contact dermatitis (skin irritation). Small patches of potential allergens are placed on your back and left for 48 hours, allowing for reactions to develop over time.

• Time: Results are seen 2-3 days after the test.
• Common allergens tested: Metals, fragrances, preservatives, and other substances that cause skin reactions.

At-Home Allergy Tests

At-home allergy tests usually involve taking a blood sample using a finger-prick device and sending the sample to a lab for testing. These kits typically test for a range of food allergies, environmental allergies, and sensitivities. However, these tests may not be as comprehensive or accurate as tests done by healthcare professionals.

• Time: Results usually take a week or two to be processed.
• Common allergens tested: Common food allergens like dairy, gluten, nuts, and environmental triggers like pollen and dust.

How Long Does an Allergy Test Take?

The duration of an allergy test depends on the type of test you are having. Here's a general timeline:

• Skin Prick Test: Typically takes 15-30 minutes to perform, with results visible within 20 minutes.
• Blood Test: May take a few days to get results, depending on the testing laboratory.
• Patch Test: Results appear 48-72 hours after application.
• At-Home Test: Usually takes 1-2 weeks for results to arrive, depending on the service provider.

How Accurate Are Allergy Tests?

Allergy tests are generally reliable, but there are some factors to keep in mind:

• False Positives: Sometimes, allergy tests can show positive results for allergens that aren’t actually causing your symptoms. This is why it's important to discuss your results with a healthcare provider.
• False Negatives: Some people may have an allergy that doesn't show up on a test, particularly with skin tests or in the case of food allergies that trigger delayed reactions.

When Should You Get an Allergy Test?

If you’re experiencing any of the following symptoms, it may be time to consider an allergy test:

• Persistent Sneezing, Itchy Eyes, or Runny Nose: Especially during certain seasons.
• Skin Reactions: Such as rashes, hives, or swelling that seem to appear after contact with certain substances.
• Digestive Issues: Such as bloating, cramps, or diarrhoea ​after eating certain foods.
• Respiratory Symptoms: Like coughing, wheezing, or shortness of breath, particularly after exposure to pets, dust, or pollen.

Final Thoughts

Allergy testing is an important step in identifying triggers that might be causing unwanted symptoms, whether they’re environmental, food-related, or something else entirely. In the UK, there are several ways to access allergy testing, from NHS referrals to private clinics and at-home test kits. Knowing your options can help you make an informed decision about what’s best for your health and lifestyle.

If you think you may be allergic to something, speak to a healthcare professional to determine which allergy test is right for you. For more information on allergy testing in the UK, visit the NHS allergy services page.

You can also explore our other articles:

• Understanding Food Allergies: Symptoms, Tests, and Treatment Options
• The Top and Most Common Allergies: Including Rare Allergies You Should Know About
• Cold or Hay Fever: How to Tell the Difference and What to Do About It