ALEX® Allergy Test

What is an Allergy?

Allergies (sometimes called hypersensitivities) develop when the body's immune system over-reacts to a substance that does not cause a reaction in most people. This is because the immune system sees the substance as harmful. The substance causing the allergic reaction is called an allergen. The immune system reacts to the allergen by producing antibodies (known as immunoglobulin E or IgE). IgE-antibodies are produced specifically for each type of allergen, and the person is sensitised. Each time the person comes into contact with the allergen, IgE-antibodies will react with the antigen and cause allergy symptoms. Symptoms are generally more severe after the first exposure (after sensitisation) to the allergen.

Allergy symptoms generally occur immediately, with symptoms appearing in minutes. They typically affect the respiratory system, gastrointestinal system, and the skin. They are caused by foods (e.g., peanuts, wheat, milk, eggs, seafood), plants (e.g., pollen, grasses), dust mites, animal dander (e.g., cat and dog dander), insect venom (wasp and bee stings), moulds, medicines (e.g., penicillin), and other substances (e.g., latex). An allergy to one allergen may mean an allergy to another (called a cross reaction); for example, an allergy to peanuts may also mean an allergic reaction occurs with soy.

Symptoms of respiratory allergic reactions include nasal congestion, sneezing, coughing, throat tightness, wheezing, and red itchy eyes, and may lead to asthma. Symptoms of gastrointestinal allergic reactions include swelling of the tongue and throat, nausea, vomiting, abdominal pain/cramps, diarrhoea and other abnormal bowel movements; and symptoms of a skin allergic reaction include hives (urticaria), red itchy rash, skin peeling, and dermatitis, and lead to eczema. Allergies may affect one body system such as hayfever (allergic rhinitis) that affects the respiratory system, or may affect all three of these symptoms such as peanut or milk allergies.

Allergies vary in severity, from a mild irritation to severe. Although uncommon, a severe reaction known as anaphylaxis, which causes urticaria, wheezing, facial swelling, low blood pressure, loss of consciousness and collapse, is potentially life-threatening.

What is an ALEX® Allergy test?

The ALEX Allergy test tests for up to 300 types of allergens at one time. The panel of allergens includes all common culprits that cause allergies, including foods, pollen, cat and dog dander, mites, insect venoms, moulds and yeasts, and latex.

A full list of allergens tested is available here: ALEX-Allergen-List.pdf

People with allergies usually have more IgE in their blood than normal. The ALEX Allergy test measures:

• The total amount of IgE-antibodies in the blood, indicating whether an allergy is unlikely, possible or an allergy is likely
• How much IgE-antibody is made in response to each specific allergen, indicating whether the test is negative/uncertain, or whether there are low, moderate, high and very high levels of IgE
• Cross reactivity between different allergens, because they contain a protein (a PR-10 allergen) that has the same structure, e.g., birch tree pollen and various foods

Why is an ALEX® Allergy test important?

Home tests for allergies bought over-the-counter can be unreliable, increasing the possibility of them giving a false result - a positive result when there is no allergy and negative result when there is. This situation can lead to a reduction in quality of life (for example, if you stop eating certain foods or it causes unnecessary worry) or to life-threatening anaphylactic shock. An ALEX Allergy test is important for accurate identification of the allergen. Once identified, a doctor can then recommend ways in which the allergy can be managed.

Who should have an ALEX® Allergy test?

The ALEX Allergy test is requested if you have symptoms suggesting an allergy.

These may include:

• Respiratory symptoms (e.g., hay fever/allergic rhinitis) that may include blocked/runny nose, sneezing, coughing, wheezing, breathlessness, and itchy red watering eyes,
• Gastrointestinal symptoms (e.g., cow's milk allergy) that may include vomiting, diarrhoea, abdominal cramps and abnormal bowel movements.
• Skin symptoms (e.g., atopic dermatitis/eczema) that may include including itchy, red, swollen, peeling skin areas.

Blood IgE allergy tests are often done when allergy skin testing is inappropriate, such as when a person takes a medicine that may affect the test results and the medicine cannot be stopped; has a skin condition that prevents accurate assessment of test results; develops urticaria when scratching their skin; or when the person could potentially have a serious allergic reaction to the allergens being tested.

Blood IgE allergy tests may also be preferred over tests known as 'challenges', where increasing doses of the potential allergen (e.g., a food or medicine) are given to the person. These tests are monitored by a doctor because there may be a risk of a serious allergic reaction.

How to test for an Allergy with the ALEX® Allergy test?

The ALEX® Allergy test tests for the allergens using a very small blood sample. The blood sample is collected by you at home using a test kit provided by your doctor. Full instructions are provided in the kit. The blood sample is collected by pricking the tip of your little finger. Emerging blood drops are collected in the collection tube, up to the top line marked on the tube. The other little finger tip can provide blood should the blood drops stop. After securing the cap on the collection tube, the tube is gently inverted several times before labelling. Finally, put the collection tube in the packing wallet and post. The ALEX® Allergy test results will be sent to a doctor at The Online Clinic who will explain whether or not you have allergies and, if you do, what you are specifically allergic to.

What are normal ALEX® Allergy test results?

The ALEX® Allergy test results will show the total IgE level in the blood. A total IgE level of less than 20 kiloUnits per litre (kU/L) indicates that an allergy is unlikely, an IgE level of 20 to 100 kU/L indicates that an allergy is possible, and a total IgE level of greater than 100 kU/L indicates that an allergy is likely.

The test will also show the IgE concentration for each allergen, which is reported as Grades ranging from 0 to 4 and as an IgE concentration in kilo Units of allergen per litre (kU_A/L). Thus,

• Grade 0 (test negative or uncertain): a concentration of less than 0.3 kU_A/L
• Grade 1 (low IgE level): a concentration of 0.3 to 1 kU_A/L
• Grade 2 (moderate IgE level): a concentration of 1 to 5 kU_A/L
• Grade 3 (high IgE level): a concentration of 5 to 15 kU_A/L
• Grade 4 (very high IgE level): a concentration of greater than 15 kU_A/L

Additionally, the test lists allergens with cross-reactivity due to the presence of the PR-10 protein.

How to minimise the risk of allergy symptoms

Because allergies are hereditary, parents have some idea of the allergies that their children may also develop. To reduce the risk of developing allergies at an early age, babies should only be fed with breastmilk or by using hydrolysed milk formulas up to aged 6 months and thereafter, given a variety of baby foods, including foods known to cause allergies. Similarly, a pet dog or cat in the first year of life may protect from allergies.

Once the allergen is identified, the key to preventing an allergic reaction is to avoid that allergen triggering the reaction. Some of the ways to prevent a reaction include:

• Food allergies: check for the allergen in food labels and lists of ingredients, and notifying the restaurant when eating out.
• Dust mites: wooden or tiled flooring rather than carpets, regular washing of bed linen, hoovering of soft furnishings/toys, wiping surfaces, and air filters
• Pets: regularly clean and groom pets (allergies are caused by their dead skin in fur, saliva, and urine)
• Mould spores: keep rooms dry and ventilated to prevent growth
• Pollen allergy: use Vaseline around the nostrils to trap pollen, wear sunglasses, check weather reports for pollen counts, and stay inside buildings as much as possible when counts are high.
• Insect stings and bites: use insect repellents and minimise skin exposure

A doctor may also recommend a medicine, e.g., antihistamines, decongestants, lotions/creams, and steroids, or allergen immunotherapy (previously known as desensitisation) whereby allergen extracts are administered to a person regularly to help increase their tolerance to the allergen.

Anyone experiencing an anaphylaxis, must be treated immediately. Adrenaline auto-injectors are prescribed for people at risk of anaphylaxis, and should be carried everywhere. Adrenaline works quickly, opening the airways, reducing swelling, raising blood pressure and relieving urticaria and gut symptoms. These auto-injectors must be used as soon as there are signs of a severe allergic reaction, and an ambulance called immediately after their use.