The information in this website is intended only for healthcare professionals. By entering this site, you are confirming that you are a healthcare professional.
The information in this website is intended only for laboratory professionals. By entering this site, you are confirming that you are a laboratory professional.
Allergy Testing Options
Guided by the allergy-focused patient history, the most appropriate next step should be testing for allergen triggers.
Types of Specific IgE Tests
Specific IgE tests such as specific IgE blood testing and skin-prick tests (SPT) can be leveraged as tools to identify sensitizing allergens and increase diagnostic certainty.1,2
Specific IgE serological tests aid in the diagnosis of allergic disease. As such, anyone presenting with allergy symptoms is a candidate for specific IgE testing.
When taking blood for a test, a 1 ml sample of whole blood is usually sufficient to test for up to 10 different allergens, although higher volumes of serum may be required to test for larger allergen profiles.
See which labs in your region have the tests you need
| Key Test Differences | Specific IgE Blood Testing | Skin-Prick Testing |
|---|---|---|
| Typically ordered and reviewed by a clinician | ✓ | ✓ |
| Patients do not need to discontinue allergy medications | ✓ | |
| Requires only one needle stick (a single blood sample) | ✓ | |
| Carries no risk of severe allergic reaction | ✓ | |
| Can be used when extensive skin rash is present | ✓ | |
| Component testing is available | ✓ | |
| Same day results in the office | ✓ |
Whole allergen and allergen components
Whole allergen
ImmunoCAP™ Specific IgE Whole Allergen provides an objective measurement of the circulating IgE antibodies and the sensitization to a specific allergen. Specific IgE antibodies appear as a result of exposure and following sensitization to an allergen. ImmunoCAP Whole Allergen measures IgE antibodies to specific allergens in human serum or plasma and allows quantitative measurements of a wide range of individual allergens and allergen components. More than 550 whole allergens and mixes are available for determinations.3*
*All allergens may not be commercially available in the United States.
Allergen components
Often, allergies are not as clearcut as a simple “yes” or “no.” That’s where specific IgE blood testing for allergen components comes in. ImmunoCAP™ Allergen Components measure specific IgE antibodies to individual molecular allergens in serum or plasma. These allergens, which are purified or recombinant proteins, offer the unique opportunity to assess a person’s allergic sensitization pattern at the molecular level. Different component groups often elicit different types of reactions, so testing them can indicate if a patient’s prior symptoms or positive test results were caused by allergy to a given substance or by a cross-reaction with another allergen. Specifically for peanuts and tree nuts, measuring specific IgE for allergen components helps the clinician weigh a patient's risk of a systemic reaction versus a more mild or localized response.4
More 100 different ImmunoCAP allergen components are available for determinations, including:
Milk
- Bos d 4 (a-lactalbumin)
- Bos d 5 (B-lactoglobulin)
- Bos d 6 (bovine serum albumin)
- Bos d 8 (casein)
Egg
- Gal d 1 (ovomucoid)
- Gal d 2 (ovalbumin)
- Gal d 3 (conalbumin)
- Gal d 4 (lysozyme)
Symptom Threshold
Up to 80 percent of patients with allergies are sensitized to more than one allergen.5 The effect is cumulative: An individual patient may have a number of triggers, which, combined, may lead to symptoms.6,7 The allergen symptom threshold is the point at which the cumulative allergen load leads to symptoms.7
Each patient has a different level of IgE antibodies at which he or she will show symptoms. Until the symptom threshold is reached, the patient will not show symptoms. However, when these allergens add up, they have a cumulative effect, pushing the patient over his or her symptom threshold.7 By reducing exposure to certain triggers, symptoms can be avoided.7
Identifying and reducing exposure to sensitized allergens, particularly house dust mite, can reduce the risk of virally induced asthma exacerbations.8 In patients with asthma, allergies and respiratory viral infections act synergistically―pushing the patient over their symptom threshold―to increase the risk of a severe exacerbation.9 Patients with asthma and allergy, who subsequently develop a respiratory viral infection, are at increased risk of hospital admission.10
Identifying all the relevant sensitizing allergens will help you outline a comprehensive exposure reduction plan to keep your patient below his or her symptom threshold.
- Duran-Tauleria et al. Allergy. 2004;59 (Suppl 78):35-41.
- Niggemann B, Nilsson M, Friedrichs F. Pediatr Allergy Immunol. 2008;19:325-331.
- PhadiaTM ImmunoCAPTM Specific IgE Directions for Use for the Phadia 250 Laboratory System. Issued September 2017.
- Matricardi P.M. et al. EEACI Molecular Allergology User’s Guide. PAI 2016;27(suppl123): 1-250.
- Ciprandi G, et al. Eur Ann Allergy Clin Immunol. 2008;40(3):77-83.
- Eggleston PA. lmmunol Allergy Clin North Am. 2003;23(3):533-547.
- Wickman M. Allergy. 2005;60 (suppl 79):14-18.
- Murray CS, et al. Am J Respir Crit care Med. 2017
- Busse WW, Lemanske RF, Gern JE. The Role of Viral Respiratory Infections in Asthma and Asthma Exacerbations. Lancet. 2010;376(9743):826 834. doi:10.1016/S0140-6736(10)61380-3.
- Green RM, Custovic A, Sanderson G, Hunter J, Johnston SL, Woodcock A. Synergism between allergens and viruses and risk of hospital admission with asthma: case-control study. BMJ. 2002; 324:763. [PubMed: 11923159]
© 2023 Thermo Fisher Scientific Inc. All Rights Reserved.