How to choose allergy tests wisely

How to choose allergy tests wisely

Healthcare is undergoing major changes, driven by increasing concerns about costs, coverage and value.

One major concern is the use of tests, procedures and therapies that are costly and may be of questionable value. To address this concern, the American Board of Internal Medicine (ABIM) has encouraged physicians and patients to think and talk about tests, procedures and treatments that may be unnecessary or even cause someone harm.

As a result, they developed the Choosing Wisely campaign to help consumers make the right choices for their healthcare. These guidelines are especially relevant for patients seeking care for allergies, including these five areas of focus for allergy treatment:

Do not perform unproven diagnostic blood tests such as an Immunoglobulin G (IgG) test or a panel of immunoglobulin E (IgE) tests to evaluate allergy.

This is one of the more common things I see in my allergy practice. Patients may have already had blood tests performed, or they request that they be done. In order to diagnose an allergy, there must be a history of exposure with cause and effect relationships. Tests can verify a suspicion that an existing problem such as hives or a food reaction is due to allergy. A trained allergist knows what the allergic conditions are and will go over a patient’s history in detail to look for triggers. The value of any allergy test is only as good as the story that supports it. The IgG test is irrelevant and its usefulness to detect a food allergy is unproven.

Random allergy testing by those who aren’t allergists — especially by using panels — may contain items that a patient has never been exposed to and thus cannot be allergic to. Patients without allergies may be diagnosed as allergic, and the results may be hard to interpret when done out of context. Tests like this can lead to unnecessary avoidance and compromise a patient’s nutrition. Patients will get rid of pets and spend needless money, and they’ll still end up seeing an allergist to interpret their test results.

Don’t order a sinus computed tomography (CT scan) or indiscriminately prescribe antibiotics for uncomplicated rhinosinusitis (i.e., a cold).

This is a tough one. Antibiotics are frequently used to fight these infections, and we need a major effort to change the perspective on this issue.

The color of the drainage does not mean a bacterial infection. Most of these illnesses are due to viruses, with only 0.05 to 2.0 percent becoming a bacterial infection. Most illnesses will resolve within two weeks without any specific treatment and they don’t require a CT scan.

Antibiotics will not help when an illness lasts less than two weeks but may actually cause resistance and side effects.

Don’t routinely perform diagnostic testing in patients with chronic urticarial (i.e., hives).

Hives scare patients. When hives occur daily for more than six weeks, they are considered chronic, and unfortunately in the majority of cases, the cause is unknown — and allergy is rarely the cause.

Medical history is the single most important part of an evaluation. Testing should be based on the patient’s story and clinical suspicion. Doing routine allergy testing is not cost-effective and is not associated with improvements or outcomes. Allergy skin testing or blood testing for allergy is not recommended for evaluating hives unless there is a very clear history.

Replacement immunoglobulin therapy for recurrent infections won’t work unless impaired antibody responses to vaccines are demonstrated.

There is a specific therapy called intravenous gammaglobulin (IVIG) used to treat recurrent infections associated with a low level of an immunoglobulin called IgG. A test is done to evaluate the immune system. When a low IgG is discovered, the next step is to look at antibody function. The use of the IVIG should be considered only to replace antibodies in someone who cannot make those antibodies. If a patient receives a diagnosis of subclass deficiency or selective IgA deficiency, IVIG should not be used unless an antibody deficiency is demonstrated. The antibody response to a vaccine is an essential part of the evaluation.

Don’t diagnose or manage asthma without spirometry.

Asthma is a disease of airflow obstruction. Spirometry measures airway flow and is an important tool in the management of asthma. Allergists cannot rely only on symptoms of asthma in diagnosing or managing asthma: Symptoms can be misleading and may be due to other conditions. Spirometry confirms the diagnosis and helps establish the severity of asthma.

During an allergy or immunology evaluation for yourself or your child, ask your allergist about the tests, procedures and treatment and be sure you are Choosing Wisely.

About this Angie's List Expert: Frederick E. Leickly, MD, MPH is a professor of clinical pediatrics at Indiana University and specializes in asthma, allergy and clinical immunology. He is the director of pediatric allergy clinical services at Riley Hospital for Children in Indianapolis.

As of May 14, 2013, this service provider was highly rated on Angie's List. Ratings are subject to change based on consumer feedback, so check Angie's List for the most up-to-date reviews. The views expressed by this author do not necessarily reflect those of Angie's List.

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