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allergen (antigen) coupled to the cellulose sponge solid phase, reacts with any specific allergen IgE in the patient's sample. Any unbound specific IgE is washed away, and an enzyme-labeled mouse monoclonal anti-human IgE conjugate is added. After an incubation period, the substrate is added, and the development of the fluorescent signal is allowed to proceed. This solution is then eluted from the sponge into a fluorometer where the resulting signal is read. The higher the signal, the greater the amount of specific IgE that was found in the patient sample, just as most common laboratory tests. The ability of ImmunoCAP to measure very small amounts of specific IgE in the patient sample results in a higher sensitivity than many other methods. This, in turn, gives physicians a more complete profile of possible allergic triggers, which can then be incorporated into an asthma action plan to help patients avoid stimuli that may lead to an asthma attack. A c c o r d i n g t o D r. R e i n h a r d t , ImmunoCAP's sensitivity and accuracy compares favorably in head-to-head comparisons with both RAST and skin testing — the most common allergy test, according to the American Academy of Allergy, Asthma, and Immunology (AAAAI) — and may be more convenient for both patients and physicians. An Easy Place to Start The first step to successfully identifying allergies is to take a thorough patient history. Patients typically recognize their susceptibilities to certain allergens, such as pets. Sometimes, though, allergic reactions may be subtle, or even develop later in life, and blood testing may effectively identif y allergens patients did not realize they had. If positive for allergy, skin tests leave irritations that present similarly to mosquito bites. While ImmunoCAP provides physicians with a more accurate method of identifying allergens, patients also benefit from its relative convenience and less irritation compared to skin testing, which subjects patients to multiple scratches or needle sticks to deliver the allergens. "One of the important advantages to the patient is that ImmunoCAP is a single needle stick to get a blood sample — compared to many sticks in skin testing," says Dr. Reinhardt. "A primary care physician can order the test from the lab, just like any other blood test." ImmunoCAP testing opens allergy testing to a broader demographic because of its compatibility with medications and nearly unlimited age range. A 2002 study published in American Family Physician notes that the use of antihistamines and medications with antihistamine-like properties must be discontinued before skin testing, an unnecessary precaution for ImmunoCAP tests. Dr. Reinhardt notes that, because many very young and very old patients may prove less reactive to skin testing, its accuracy may be suspect in these populations. ImmunoCAP, he says, has demonstrated safety and efficacy in patients as young as three months and older. THERMO SCIENTIFIC AT A GLANCE IN MORE THAN 40 years, the ImmunoDiagnostics business of Thermo Fisher Scientific (formerly known as Phadia) has developed, manufactured and marketed complete blood test systems to help clinicians across the globe diagnose and monitor allergy, asthma and autoimmune diseases. Robert Reinhardt, M.D., U.S. Medical Director for the ImmunoDiagnostics business of Thermo Fisher Scientific, recalls the early days of the company's development of allergy testing methods, when the focus was on developing and perfecting the radioallergosorbent test (RAST). In the 20 years since, allergy testing has improved significantly with the company's introduction of ImmunoCAP blood testing, which is designed to more accurately detect specific immunoglobulin E (IgE) in patients' blood. Thermo Scientific's four centers of excellence are located in southern Sweden; Freiburg, Germany; Vienna, Austria; and its headquarters in Uppsala, Sweden. "It's helpful to identify the allergens triggering winter asthma by allergy testing. The National Institutes of Health asthma guidelines say skin or blood testing may be used to identify offending allergens. If physicians do that and put into place a specific allergen avoidance program targeted to a patient's allergen sensitizations, then severe asthma conditions may be reduced by as much as 50%. Even though physicians can't do much about inevitable viral infections, physicians can address patients' exposure to triggers." — Robert Reinhardt, M.D., U.S. Medical Director for the ImmunoDiagnostics business of Thermo Fisher Scientific MDNEWS.COM I MD NEWS Twin Cities | 13

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