Private ALEX Allergy Testing
ALEX (Allergy Explorer) is a specialist blood test that measures specific immunoglobulin E (IgE) antibodies to a wide range of allergens using a single blood sample. It may help investigate suspected allergies to foods, pollens, dust mites, animal allergens and other substances.
What is ALEX allergy testing?
ALEX stands for Allergy Explorer. It’s a type of multiplex blood test that measures specific IgE antibodies to multiple allergens at the same time, rather than testing for individual allergens one by one.
IgE is an antibody produced by the immune system. In people with an IgE-mediated allergy, the immune system produces IgE that recognises substances that would normally be harmless, such as certain foods, pollen, house dust mites, or animal allergens.
ALEX uses molecular allergy diagnostics, also known as component-resolved diagnostics. As well as testing whole allergen sources, it can identify IgE antibodies that recognise individual proteins, or components, within certain allergens.
This additional information can help your allergy specialist assess patterns of sensitisation and investigate possible cross-reactivity. Cross-reactivity occurs when IgE recognises similar proteins found in different substances. For example, someone sensitised to pollen may also have a positive result to a similar protein in a food without necessarily having a clinically significant food allergy.
A positive specific IgE result indicates sensitisation, but it does not automatically mean that you have a clinical allergy. Whether sensitisation causes symptoms depends on your clinical history and how your body responds to exposure.
At Welbeck, our allergy consultants assess whether ALEX testing is appropriate for your symptoms and medical history. They interpret your results alongside your clinical history to help distinguish allergic sensitisation from a clinically significant allergy and determine whether further investigation or treatment is needed.
ALEX testing is not suitable for everyone and cannot diagnose every type of allergy. A specialist consultation helps determine which investigations are most appropriate for you.
All consultations and follow-up appointments take place in our dedicated Allergy centre, with bloods taken in our on-site Imaging & Diagnostics centre.
Paediatric ALEX allergy testing
Welbeck offers paediatric allergy appointments for children aged 0 and above. Your child's consultant will assess their symptoms and medical history to determine which investigations are appropriate.
For more information, visit our Paediatric Allergy service page.
More information
ALEX testing can assess sensitisation to a wide range of allergens from a single blood sample. Depending on your symptoms and medical history, it may help your consultant investigate complex patterns of suspected allergy.
Your consultant may consider ALEX testing if:
you have symptoms that suggest possible allergies to several different substances
your medical history suggests that a more detailed assessment of allergen sensitisation may be helpful
understanding possible cross-reactivity between allergens could help guide further investigation
ALEX testing is not necessarily more appropriate than targeted allergy blood tests or skin prick testing. The best approach depends on your symptoms, previous reactions, and the clinical question your consultant needs to answer.
Depending on your symptoms and medical history, your consultant may recommend ALEX testing to investigate possible sensitisation to:
foods: including milk, egg, nuts, grains, fish, shellfish, and fruits and vegetables
pollens: including tree, grass, and weed pollens
dust mites: including house dust mites and storage mites
animal allergens: including those associated with cats, dogs, and other animals
airborne allergens: including moulds
other allergens: such as latex and selected insect venoms
A broad panel can be helpful in selected cases, but testing more allergens does not automatically provide a better answer. Testing substances that are not relevant to your symptoms can produce results that are difficult to interpret.
Your consultant may recommend a more targeted investigation instead, such as skin prick testing or a blood test for specific individual allergens.
Please note that ALEX testing is designed to investigate IgE-mediated allergic sensitisation. It is not a food intolerance test and cannot diagnose conditions such as lactose intolerance or coeliac disease. It also cannot confirm drug allergy, so suspected reactions to medicines require appropriate specialist assessment, which may include drug provocation tests and challenges.
ALEX testing at Welbeck begins with a specialist allergy assessment. Your consultant will review your symptoms, previous reactions, medical history, medicines, and any previous allergy test results before deciding whether the test is appropriate.
If ALEX testing is recommended, a blood sample will be collected, usually from a vein in your arm.
Your appointment will typically involve the following steps:
Clinical assessment: Your consultant will discuss your symptoms, when they occur, possible triggers, and any previous allergic reactions.
Choosing the appropriate test: Your consultant will decide whether ALEX testing is likely to provide useful information and whether other investigations may be needed.
Blood sample collection: A small blood sample will be taken for laboratory analysis.
Laboratory analysis: The sample will be tested for specific IgE antibodies against allergens included in the selected ALEX panel.
Results and interpretation: Your consultant will explain the findings in the context of your symptoms and medical history and discuss any recommended next steps.
The laboratory report may identify sensitisation to several allergens or individual allergen components. A positive result does not necessarily mean that you will experience symptoms when exposed to that substance.
Your consultant may recommend additional investigations, such as skin prick testing, targeted specific IgE blood tests or, in selected cases, a medically supervised food challenge. The appropriate approach will depend on your symptoms, history, and individual risk.
ALEX testing involves taking a blood sample rather than deliberately exposing you to suspected allergens. The test itself is therefore not designed to trigger an allergic reaction.
As with other blood tests, minor side effects can occur, including:
brief discomfort when the needle is inserted
mild bruising or tenderness at the needle site
a small amount of bleeding
feeling light-headed or faint
Your clinical team can advise you if you have concerns about blood sampling or have previously felt faint during a blood test.
Your Welbeck consultant will advise you whether you need to do anything before your appointment.
Do not stop taking antihistamines or other prescribed medicines unless your treating clinician has advised you to do so. In most cases, fasting is not required for this type of blood test, but follow any specific instructions provided by your clinical team.
To help your consultant assess your symptoms, it may be useful to bring:
details of previous allergic reactions and when they occurred
information about foods or other substances you suspect may trigger symptoms
photographs of rashes or swelling, where relevant
results from previous skin prick tests or blood tests
a list of medicines and any supplements you take
details of any adrenaline auto-injectors or allergy action plans you have
If you have experienced a severe allergic reaction, tell your consultant what happened, how quickly your symptoms developed, as well as what you had eaten, touched, inhaled, or otherwise been exposed to beforehand.
As ALEX testing involves a blood sample, you can normally return to your usual activities immediately afterwards.
The next step is to review the results with your consultant. ALEX reports can contain a substantial amount of information, so your consultant will focus on the findings that are relevant to your symptoms and medical history.
Do not make major changes to your diet based on an allergy blood test alone. Removing foods unnecessarily can make it harder to maintain a balanced diet, particularly for babies and children. Seek appropriate clinical or dietetic advice before making significant dietary changes.
If your results and clinical history suggest a potentially important allergy, your consultant will explain what the findings mean, whether further tests are needed and how to manage any confirmed allergy. Depending on your diagnosis, this may include advice on avoiding specific allergens, managing accidental exposure, medicines, or emergency treatment.
For information about the cost of private ALEX allergy testing at Welbeck, please contact our Allergy centre.
Our team can explain the appointment process and the costs involved, including any relevant consultation or follow-up fees.
If you have private medical insurance, check your insurer's authorisation requirements before proceeding. Self-pay options are also available.
At Welbeck, our allergy service provides consultant-led assessment and investigation to help patients understand their symptoms and identify appropriate next steps.
Our consultants interpret allergy test results alongside your medical history and clinical presentation, helping to distinguish clinically relevant allergies from sensitisation that may not cause symptoms.
Where appropriate, your consultant can recommend further investigations or coordinate care with other specialties within Welbeck. This approach helps ensure that decisions about testing and treatment are based on your individual needs.
ALEX testing at Welbeck requires a referral from your GP or an allergy specialist following a consultation. Self-referrals are not accepted for this test.
If you have been advised to consider ALEX testing, contact our Allergy centre to discuss the referral process, appointment arrangements and costs.
Welbeck accepts patients with private medical insurance, subject to the relevant insurer's authorisation requirements, as well as self-paying patients. Please check your cover and any required authorisation before proceeding.
Contact our team to find out more about arranging an allergy consultation.
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Frequently asked questions
ALEX testing can provide information that helps your consultant assess the risk of an allergic reaction. Sensitisation to certain allergen components, such as Ara h 1, 2,3, 6 in peanut or Cor a 9 and Cor a 14 in hazelnut, is associated with a greater likelihood of systemic reactions than sensitisation to some other components.
However, component results cannot reliably predict how severe an individual reaction will be. Your consultant will interpret your results alongside your symptoms, previous reactions and medical history to assess your individual risk.
If you may be at risk of a serious allergic reaction, your consultant will explain how to manage that risk, including avoiding relevant allergens, recognising symptoms, and whether you need emergency medication.
No. ALEX is designed to investigate IgE-mediated allergic sensitisation. Food intolerances generally involve different mechanisms and cannot be diagnosed by measuring allergen-specific IgE.
If your symptoms are more consistent with a food intolerance, your consultant can recommend a more appropriate investigation.
Sensitisation means that your blood contains specific IgE antibodies that recognise a particular allergen. A clinical allergy occurs when exposure to that allergen causes symptoms.
You can therefore have a positive specific IgE result without becoming unwell when you encounter the substance. This is why your symptoms and medical history are essential when interpreting ALEX results.
No. ALEX tests for allergens included in the selected panel and is designed to investigate IgE-mediated allergic sensitisation. It cannot diagnose every type of allergy, and a negative result does not necessarily explain or rule out every cause of your symptoms.
Your consultant will consider whether other investigations or a different diagnosis should be explored.
Your consultant will review your results alongside your clinical history and consider whether further investigation is needed.
Depending on your symptoms, this may include targeted specific IgE blood tests, skin prick testing, intradermal testing, or another specialist assessment. In selected cases of suspected food allergy, a medically supervised food challenge may also be considered when clinically appropriate.
Allergy assessment is rarely based on a single test, particularly when the results do not match your symptoms.