Making allergy testing routineEnhance patient care with a simple blood test for specific allergens
Allergies are common and affect people of all ages, genders, and ethnicities. Reported allergies are more prevalent than ever and are sending increasing numbers of people to hospitals on a global scale. The WHO estimates that 20% of the global population suffers from IgE-mediated allergic diseases, placing heavy financial strains on clinician and hospital resources, particularly in emergent situations.¹
Allergic reactions can range from mild to severe and manifest themselves as allergic asthma, allergic rhinitis, allergic conjunctivitis, atopic eczema/atopic dermatitis, or anaphylaxis. These manifestations may vary between adults and children. Hospitalization for allergy-related anaphylaxis is on the rise in the U.S., Australia, Europe, and other regions.²
Allergy diagnosis
The guideline supported by both European- and U.S.-based allergy organizations for allergy diagnosis includes a medical history, physical exam, and testing by either an in vitro method (such as 3gAllergy™) or an in vivo method (skin prick testing) to aid in diagnosis.³
Allergies are diagnosed by beginning with a clinical history and physical examination, followed by in vivo testing and in vitro testing.
Allergy testing
Allergy testing can be performed by in vivo or in vitro methods. In vivo testing involves a skin prick test (SPT), which is often the first-line approach to determine the release of allergen-specific IgE antibodies. However, in vitro testing with highly purified allergens or recombinants can be used as an alternative or complementary diagnostic tool.4
Using a small serum sample, the laboratory measures specific IgE antibodies to many different allergens.
In vitro specific IgE testing may be indicated over SPT:4,5
- When the SPT test is negative but there is a high clinical suspicion
- In patients with eczema
- In patients taking tricyclic antidepressants
- In very young or older patients who may have a reduced histamine response
- In patients with an increased risk of anaphylaxis
- In pregnant women
In vitro allergy blood testing supports improved patient outcomes:
- Convenient method for monitoring decreases in sensitization resulting from a medical intervention such as allergen avoidance
- Valuable diagnostic tool for following development and prognosis of sensitization in childhood
- Convenient for patients suffering from eczema, atopic dermatitis, and other skin conditions
- Practical for geriatric and pediatric patients affected by dermatographism
- Convenient method for pediatric and geriatric patients
- Easy to perform, with one simple blood draw to obtain multiple determinants
- Reduced risk of anaphylaxis
- No skin reactions
- No need to stop patient’s medications, as there is no interference with medications such as antihistamine H1 blockers, H2 antagonists, or tricyclic antidepressants6
- Good correlation with patient clinical history and skin tests7
- Readily available to primary care physicians
Cross-reactive carbohydrate determinants (CCDs) in allergy testing
CCDs are carbohydrate structures present in many plants and insect allergens. These structures are not recognized by IgE antibodies specific to the allergen itself, but they can bind to IgE antibodies specific to CCDs. This can lead to false-positive results and clinical overestimation of a patient's sensitization to certain allergens.8
Therefore, it is important for laboratories performing in vitro testing to include controls that can detect the presence of CCD-specific IgE antibodies and interpret the results with caution, particularly when testing for allergens that are known to contain CCDs.8,9
IMMULITE® 3gAllergy™ liquid allergen technology is a bead-based approach that reduces the need for additional allergy testing and the risk of false-positive results.
3gAllergy
The IMMULITE® 2000/XPi 3gAllergy™ – Allergen-specific IgE assay helps to enhance patient care with reliable results from a simple blood test that uses quality extracts thoroughly evaluated for potency and allergenic composition. The assay provides reliable results as an aid in the clinical diagnosis of IgE-mediated allergic disorders.
The 3gAllergy menu includes over 350 allergens, panels, and components across animals, drugs, dust, foods, grasses, insects, mites, molds, occupational, parasites, trees, and weeds.
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J Allergy Clin Immunol Pract. 2020 Apr;8(4):1216-18.
American Academy of Allergy, Asthma & Immunology. Allergy diagnosis in clinical practice. 2006 Nov.
Klimek L, Schendzielorz P. GMS Curr Top Otorhinolaryngol Head Neck Surg. 2008;7:Doc04. https://pubmed.ncbi.nlm.nih.gov/22073091/
AAAAI. Children. Accessed Jan 2022.
Olert M, et al. Allergen-specific IgE measured by a continuous random-access immunoanalyzer: interassay comparison and agreement with skin testing. Clin Chem. 2005;51(7):1241. https://pubmed.ncbi.nlm.nih.gov/15905313/
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