Phadia Allergy Tests and Asthma

In today’s (October 15, 2009) Indianapolis Star there was a very nice article by Shari Rudavsky. The article ‘Breathing Easier’  focuses on an entire family that struggles with asthma. This sharing of the human experience is very important for others who have asthma. Those who struggle with asthma are not alone. We can all learn from others who are willing to share their experiences. I want to extend a very warm ‘thank you’ to Ms. Rudavsky for her work.

 The article did contain something that I strongly feel needs to be critiqued and clarified. The content expert for the quote was an associate professor of family practice at Michigan State University. Dr. Reinhardt is quoted as saying that the National Heart, Lung, and Blood Institutes (NHLBI) Guidelines for the Diagnosis and Management of Asthma 2007 advocates the use of the Phadia test to determine whether a person has allergies to common indoor allergens. He also states that too few clinicians are using this test.

 The first comment is out of context with other considerations that need to be addressed prior to ordering an expensive and perhaps unreliable laboratory test. The comment supports one commercially available product (fair balance). It assumes that this commercial product is the one the Guidelines recommend. As to the last comment regarding the use of the Phadia test for inhalant allergens, this is most probably because clinicians may be aware of the problems with this approach to allergy.

 The 2007 asthma guidelines do not specific the Phadia test for determining allergy. On page 168 of the NHLBI Asthma Guidelines Key Points clearly indicate that there are more steps involved- a relevant history, skin testing or in vitro testing, and an assessment of the significance of the test results. The guidelines do not mention specifically the Phadia test in the Key Points. This test has value, but only in the context of a patient’s history. The Phadia test for inhalant allergens is frequently falsely positive. In a recent national survey (JACI 2009;123:1163-9) 20% had symptoms of allergic disease. The Phadia test for inhalants demonstrated that 50% of the population had a positive test (for more on this article see ‘Incidence of Allergy in Children: Using Allergy Testing Panels (Pharmacia ImmunoCap) or Symptoms?’ one of my earlier posts on this topic). It is very important to point out that any test used in allergy only tells us that antibodies are produced. It is the history of symptoms plus the results of the test together that fulfill the criteria for allergy. A test result alone makes no one allergic and is only as useful as the history that supports it.

 In my opinion the reason why the Phadia test is not being used is because clinicians are aware of the need of taking a history, they dislike the obligatory panel of analysis offered by the Phadia panel, there is worry about the cost, and the test declares many more positive than actually have symptoms.

 Do we let the laboratory test dictate the diagnosis/treatment or the patient’s history matched to relevant laboratory studies to decide how to manage asthma?

I am old school- I make sure that I understand the history of the condition and the environmental exposures. From this I decide what tests for allergy are relevant and use testing to verify my clinical impression. Sometimes we don’t need to test. Sometimes we have to take the test results and re-evaluate the history and exposures to make sense of it all. Health care is expensive, laboratory tests for specific IgE is expensive. The consequences of questionable results taken out of context can have a cost as well. Allergen-environmental control is a big business. Consider the hidden costs of extra work, alteration of living environments, and the status of pets. Seek out consultation of experts who can sort through both a medical and environmental history and make sense of what to test for. You also need to consider what the gold standard is for the assessment of allergic sensitization and that is the allergen skin prick test. Look also to the credentials of the providers that you are working with.

Fred Leickly

October 15, 2009 · fleickly · 6 Comments
Posted in: Allergy Testing, Asthma, Phadia Allergy Tests

6 Responses

  1. Patricia Eaton - October 28, 2009

    Most of your comments are valid and highly valued. Although, I have worked as an asthma specialist for years and totally disagree with your interpretation and feelings toward in-vitro testing. In-vitro testing has advanced well beyond skin or intradermal testing and I believe allergists (such as yourself) are only being self-serving by berating them to help your high cost allergy skin tests (in my mind, they’re archaic). I agree that history and exposure must be considered with all patients, especially with the improved sensitivity of in-vitro testing.
    There are currently more than 23 million asthmatics in the US and only around 4 thousand allergists. Most asthmatics must be managed by primary care providers. We can not even fathom the thought of referring all of our asthmatics to allergists (nor is it possible). We have no other options.
    Even if skin testing was superior to in-vitro testing, it is a total disservice to patients to dissallow them to know the ‘root of their problem’. We test with the immunocap test daily to uncover the triggers that are causing symptoms.
    One of my physicians just showed me two studies that confirmed that allergy specialists (such as yourself) can not guess sensitivities based on history and physical alone by more than 50%. Therefore, we need profiles that allow us to test for the most relevant allergens in our area. We, of course, still take history and exposure in to consideration, and tailor our treatment accordingly.
    I hope you and your allergist collegues feel good with your futile and self-serving vendetta against in-vitro testing for allergies.
    Do you want to talk about allergy component testing? I bet not…Catch up buddy.

  2. fleickly - November 13, 2009

    Thank you for taking the time to read the BLOG and making a comment. You present a number of issues that I will address in a new Home Page posting.

  3. Allergies: A Leickly Story » Blog Archive » Responding to Criticism- Phadia Immunocap Testing - November 13, 2009

    […] The comment in question was posted to my October 15, 2009 entry titled Phadia Allergy Tests and Asthma . […]

  4. Randy Hollopeter - April 27, 2010

    ThanksHi, very useful info, I love how easy it is to surf, I will keep visiting for more.Thank you.

  5. fleickly - April 27, 2010

    I try my best. Thank you for the comments.

  6. Hailey Hall - September 30, 2010

    asthma simply sucks! i suffer from it for several years already,*;