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ImmunoCAP Specific IgE Blood Test
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Is ImmunoCAP Specific IgE blood testing as good as skin-prick testing?
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How does the ImmunoCAP Specific IgE blood test compare with other
IgE assays? -
How was the respiratory profile designed? How are the allergens selected?
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Which laboratories in my area offer ImmunoCAP Specific IgE blood testing?
How can I be sure that a pre-selected allergy profile will include the specific allergens affecting my patient?
A: ImmunoCAP profiles contain a relatively small number of allergens, but you can rest assured that each profile includes allergens known for their cross-reactivity with common pollens or inhalant allergens and strong prevalence in the patient’s environment. Sensitivity to many allergens, such as pollens, will reflect similar results from other allergens within the same species. In addition, the ImmunoCAP respiratory disease profiles have been selected based on the prevalence of indoor and outdoor allergens common to particular regions, such as pollens specific to certain geographic areas. In children, meanwhile, six foods account for 90% of food allergy reactions. The ImmunoCAP childhood allergy profile (also referred to by various labs as the “Allergy March Profile” or “Pediatric Profile”) includes not only key food allergens but also indoor inhalant allergens that have been selected to reflect common sensitivities in young children. By utilizing representative allergens, as well as careful calibration of specific IgE levels, ImmunoCAP profiles are engineered to detect more than 95% of allergic patients. In addition, if a patient or parent suspects allergy based on a clinical response to a specific allergen, you could test for that allergen as well.
Is ImmunoCAP Specific IgE blood testing as good as skin-prick testing?
A: ImmunoCAP is a cutting-edge allergy assay, offering highly reproducible results. The pre-selected regional inhalant allergy profiles are capable of detecting more than 95% of patients with allergy. This technology compares quite well with skin-prick testing. Echoing the views of several allergy specialists on the current state of the technology, Robert G. Hamilton, director of The Johns Hopkins University Dermatology, Allergy and Clinical Immunology Reference Laboratory, has observed that in vitro blood testing and skin-prick testing can be viewed as interchangeable.
How does the ImmunoCAP Specific IgE blood test compare with other
IgE assays?
A: ImmunoCAP features state-of-the art technology that performs vastly better than other allergy assay methodologies, including the radioallergosorbent test (RAST). Unlike the RAST paper disc, the ImmunoCAP reaction vessel contains a cellulose polymer sponge. This cellulose polymer binds almost 150 times more protein than a passively coated tube, well, or bead, and 250% to 300% more protein than a paper disc. This enhanced binding capacity (along with optimized test automation) translates to superior test results, as several studies have shown. Data published in the Journal of Allergy and Clinical Immunology demonstrated that ImmunoCAP was 96% to 98% accurate in identifying and quantifying specific allergens, while modified RAST tests were only 65% to 82% accurate.
How do I know which ImmunoCAP profile to order?
A: Nineteen pre-selected regional inhalant profiles are available. These profiles are based on the prevalence of indoor and outdoor allergens common to particular regions. So all you have to do is select the profile for your region. I have found that the ImmunoCAP profile for my particular region is highly effective at detecting specific allergic sensitivities, in part because it includes allergens known to have high cross-reactivity—that is, those that elicit patient sensitivity similar to certain other allergens within the same species. For younger children, particularly the infant or preschooler, the ImmunoCAP Childhood (Allergy March) Profile tests for key food and inhalant allergens, selected to detect sensitivities common in children. This test is good in distinguishing which child may have symptoms due to allergies and would be subsequently at risk for the development of allergic asthma. However, testing a more comprehensive range of allergens, including additional foods and/or inhalant allergens, may provide more useful information when the clinical scenario dictates it, even in children as young as 3 months of age.
How was the respiratory profile designed? How are the allergens selected?
A: To aid in the process of choosing allergens for testing, pre-selected ImmunoCAP multi-allergen profiles have been developed. Regional inhalant profiles are based on the prevalence of indoor and outdoor allergens common to particular regions, such as pollens specific to certain geographic areas. In addition, allergist ordering patterns were examined to see which allergens are most often tested by specialists in each region. ImmunoCAP profiles have been engineered to include inhalant allergens characterized by high cross-reactivity—that is, allergens that elicit patient sensitivity similar to certain other allergens within the same species. In children, six foods account for 90% of food allergy reactions. The ImmunoCAP Childhood (Allergy March) Profile includes not only key food allergens but also inhalant allergens to reflect common sensitivities in children.
Can I order individual allergens?
A: Yes. Most laboratories offer ImmunoCAP Specific IgE testing for hundreds of inhalant and food allergens. Nevertheless, I recommend that you also order a profile of pre-selected allergens. When testing for a single allergen, you may not get the patient’s whole allergic picture. You see, patients are often sensitized to more than one allergen (polysensitized), so a pre-selected profile will help you to detect a broader range of possible sensitivities. Also, allergy is a cumulative threshold disease. Symptoms of atopic illness are often triggered only after exposure to multiple allergens. The patient who is sensitized to more than one allergen crosses the symptomatic threshold only after a cumulative allergic load has been reached. I usually test with a profile, and make sure that any specific suspect allergens turned up by patient history are covered. If not, then I order those in addition to the profile.
A: It’s easy. ImmunoCAP is available in pre-selected profiles so you don’t have to decide which allergens to test. In adult respiratory disease, these consist of the most common regional seasonal and perennial inhalant allergens, along with total IgE. These are the Respiratory Allergy Profiles, and 19 are available, tailored to different regions in the US. Likewise, children with common symptoms may be tested effectively with a profile consisting of key food and inhalant allergens, along with total IgE, which is called the Allergy March Profile (also referred to as the childhood allergy profile or pediatric profile).
How long does it take to get the results?
A: ImmunoCAP test results are reported back to the ordering clinician in about two to three days, depending on the turnaround time of the individual laboratory. It may take longer, so check with your laboratory.
Which laboratories in my area offer ImmunoCAP Specific IgE blood testing?
A: Click here to locate the lab closest to you that offers ImmunoCAP testing. You may also call a customer service specialist toll-free at 877-862-4948 for additional information.
What are the specimen requirements?
A: All it takes is a single blood sample. 40 microliters + dead volume is usually needed per allergen, so 1 serum separator tube or spun barrier tube (red top) is required for a panel of allergens. EDTA plasma may also be used (ImmunoCAP Specific IgE procedure). Specimens should ship at room temperature and they can be stored at 2° to 8°C for up to 1 week. Please contact your laboratory to determine the exact quantity of sample they require per test.
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