Allergen-Specific IgE Testing

Allergies

The development of an allergic response begins with initial sensitisation to an allergen and the production of specific Immunoglobulin E (IgE). While the presence of this antibody mediates the reaction, only susceptible individuals will progress from asymptomatic sensitisation to the development of clinical allergy, with symptoms as outlined below.

Allergy Testing Doctor Brochure

Allergy Testing Order Form

Recognising allergic symptoms
Allergic reactions can affect many parts of the body and symptoms may vary from mild to severe. These include:
- asthma or chronic cough
- rhinitis (runny nose)
- conjunctivitis (weepy eyes)
- atopic dermatitis (itchy skin/eczema)
- urticaria (hives)
- upset stomach and bowel
Anaphylaxis is a less common but far more serious reaction that affects the whole body. It can be life-threatening and requires urgent medical treatment.
Clinical assessment and history
General practitioners should take a detailed history, with particular attention to:
- timing of symptom onset
- nature and extent of symptoms (organ systems involved)
- duration of symptoms
- reproducibility of symptoms
- factors that induce or modify symptoms (e.g. exercise, heat)
These may be obvious, particularly with food allergy, where oral symptoms may arise within seconds to minutes following exposure (Oral Allergy Syndrome – OAS), or they may require a more detailed examination of the environment.
Some simple approaches may be useful in patients with limited allergies:
- pollens are prominent outdoors in spring and summer
- moulds indoors, especially in winter (but possibly perennial)
- house dust mite indoors and year-round
- animal dander following specific exposures
This information is important in selecting laboratory testing of specific IgE, which can be used to manage severe or nuisance allergies through avoidance and/or immunotherapy.
Common allergens
1. Respiratory allergens (e.g. house dust mite, pollens, animal dander, moulds): respiratory symptoms commonly reflect allergy to inhaled allergens, although they may accompany other allergic symptoms across a wide range of exposures.
2. Food allergens (e.g. egg, cow's milk, peanut, tree nuts most commonly cashew, pistachio, hazelnut and walnut), sesame, soy, fish, shellfish, wheat): food ingestion may result in a variety of clinical manifestations, ranging from OAS and skin reactions to life-threatening anaphylaxis. Most food allergens are primarily managed by avoidance, so it is important to correctly identify the relevant allergen, as diets can be intrusively restrictive and lead to poor adherence.
3. Insect venoms: these are important causes of allergy, including anaphylaxis. Insect allergens may also cause respiratory or skin symptoms.
4. Adverse drug reactions: adverse drug reactions can be classified as Type A (predictable) or Type B (unpredictable or idiosyncratic). Type B reactions include allergic reactions that may be IgE-mediated immediate responses, including anaphylaxis, or several cell-mediated immune responses. Clinical history is crucial in assessing drug reactions of all types. While serum-specific IgE is available for investigating some potential drug allergies, specialist clinical assessment may be required.
Allergen-specific IgE testing

Laboratory allergy testing detects allergen-specific IgE in serum. Testing is available for a wide range of food and environmental allergens. It is an important tool in diagnosing IgE-mediated food allergy and insect venom allergy, and some forms of drug and latex allergy. It also assists in managing allergic conditions such as asthma, eczema, or allergic rhinitis by identifying relevant allergic triggers.
Serum-specific IgE is best used to confirm allergen specificities once a clinical diagnosis of allergy has been made.
Clinical Labs offers a wide selection of serum-specific IgE tests, which can be considered according to the patient’s symptoms. To view our current offering, download our doctor brochure or order form below.
Allergy Testing Doctor Brochure Allergy Testing Order Form
Benefits of allergen-specific IgE testing
- Can be ordered by a GP while the patient awaits their specialist appointment
- Can be performed when there is extensive skin disease
- Not affected by medications (e.g. the patient does not need to stop antihistamines or steroids)
Selecting specific allergen(s)

Clinical history is the most important factor when considering serum-specific IgE testing and will guide you as to which allergen tests to order. Where clinical history informs requests for specific allergens, allergen-specific IgE testing offers accurate, easy-to-interpret and reliable results in most cases.
The use of allergen mixtures (e.g. food mix) for specific IgE is not recommended. However, if there is no clear indication of the allergen*, panels are available to screen for common food or respiratory allergens. These suffer from a lack of sensitivity due to dilutional effect or may produce more false positives due to the additive effect.
*This applies when the history is not helpful, the patient is too young to provide details, or the response appears allergic but the history is unobtainable or not discriminatory.
Interpreting serum-specific IgE results

A positive specific IgE does not always equate to clinically significant allergy and must be interpreted in the context of clinical history.
Higher concentrations of specific IgE are more likely in symptomatic allergy and may correlate with disease. However, consumption of antibodies during anaphylaxis may produce false-negative results, necessitating a delay of 10 days to 3 weeks for optimal testing.
Results obtained with modern serum-specific IgE detection technology correlate well with skin prick tests. Laboratory investigations may be used to identify specific allergens for ongoing management of an individual's allergies.
When to refer to a specialist
Referral to a specialist allergist should be made in the case of:
- all anaphylaxis
- suspected food allergy (especially where allergen immunotherapy is considered)
- asthma requiring the use of preventer therapy
- allergic rhinitis that has failed to respond to medical therapy
- suspected latex and drug allergy
- systemic reactions following insect stings
How to Order Allergen-Specific IgE Testing
Request Form Instructions:
- Complete a Clinical Labs General Pathology Request Form, specifying serum-specific IgE testing. To indicate the specific allergens or mixes required, use the Allergen-Specific IgE Order Form.
- Please be as specific as possible in your selections, based on the patient’s detailed clinical history.
- Blood samples can be collected at any Clinical Labs collection centre.
Please note:
- Allergen mixes are best used to refine the direction of individual allergen requests, which have better sensitivity and specificity prior to treatment.
- In children, due to lack of sensitivity and specificity, and to prevent unnecessary food avoidance, testing for individual allergens is preferred over mixes.
- When one penicillin allergen is ordered for sensitivity testing, such as Amoxycillin, Clinical Labs will routinely test all four available penicillins individually as standard practice.
Test Cost:
- Medicare will fund up to four patient episodes of Allergen-Specific IgE testing within any 12-month period. Each episode may include four single allergens, four allergen mixes or any combination of four allergens and mixes. If tests are not ordered together, each additional episode will require a new referral and specimen collection. Any tests requested beyond this limit will incur an out-of-pocket cost to the patient.
- Test requests beyond this limit will incur an out-of-pocket cost to the patient of $15 per individual allergen or allergen mix.