Ask The Advocates: What Tests Were Used to Diagnose Your Asthma?

Everyone's asthma is different, it isn't a one size fits all condition. Understanding the tests needed to be done for a proper and official diagnosis can be helpful when understanding your specific asthma. Our advocate team of respiratory therapists and asthma educators help us answer the question:

What asthma diagnostic tests were used to diagnose your asthma?

Response from Ms. Al Veoli, AE-C

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A spirometry test officially diagnosed my asthma when I was in my 40’s. However, I was “told” I had asthma in college, and treated for 20+ years without any diagnostic testing. My health care providers did not follow best practices for diagnosing asthma from the National Heart Lung & Blood Institute (NHLBI), which includes lung function testing such as spirometry. Listening to your lungs and taking a history of symptoms are important, but should not take the place of spirometry.

Response from Leon C. Lebowitz, BA, RRT

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There are any number of tests used to diagnose asthma. First and foremost, a physician who is educated and trained in the treatment of pulmonary disease should be contacted. Following a complete history and physical examination, the physician may order the following diagnostic tests: a chest x-ray, pulmonary function testing and even an arterial blood gas. These diagnostic tests are commonly used to help in the diagnosis of asthma. The initial chest radiograph or x-ray will provide the baseline imaging evaluation for a patient being evaluated for an asthma diagnosis. This image can help to evaluate and differentiate between asthma and other conditions which may mimic asthma. Serial x-rays will help determine changes to the lung over time and the extent of those changes.

Pulmonary function testing (PFT) is the principal mainstay for a diagnosis. The results help the doctor evaluate the condition of the lung. PFT's measure lung volumes, capacities, and flow rates to determine if asthma is present and the severity to which it is involved. It can also demonstrate how constricted the airways are and if they are responsive to medication (bronchodilators). The airways can be 'challenged' (or tested) to assess how sensitive they are. Finally, PFT's can assess the changes to the lung over time if used on a systematic basis.

A peak flow meter is a device that a patient may use regularly at home to help measure the level of airway obstruction. Serially monitoring one's peak flow rates can help the patient keep an eye on trending at home. This can be instrumental in determining when to change medication usage or seek assistance from one's health care team.

Allergy testing and history are used when asthma symptoms seem to persist over time, and may be related to triggers that an individual may be exposed to constantly (e.g. indoor allergens, occupational and environmental triggers).

Arterial Blood Gas (ABG) may be used during acute attacks/exacerbations or during hospitalizations. The results of ABG's help to quantify how well oxygenation and carbon dioxide exchange is occurring in the asthmatic lung. As well, it shows the acid base status of the patient's condition as it relates to the efficiency of one's breathing during the exacerbation.

Pulse Oximetry provides the oxygen saturation level in the (arterial) blood and can assist in monitoring one's oxygenation in lieu of the invasive ABG. Trending the saturation and it's stability may be of value for the patient at home or when ABG's are no longer warranted.

What diagnostic tests were used in the evaluation of your asthma? Have you had any of those mentioned above?

Response from Lyn Harper, MPA, BSRT, RRT

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First was a thorough physical exam that included a detailed medical history. This included all the times I had symptoms, however minor. Where I was, what I was doing, and how long it lasted. Second was a full pulmonary function test or PFT. The results are broken into three categories – Normal, Obstructive, and Restrictive. Asthma is considered an obstructive airway disease. Allergy testing was next as it had become fairly apparent that I had allergy induced asthma.

Response from Theresa Cannizzarro, Respiratory Therapist

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Along with a detailed medical history and physical exam, the test that is done to give the official asthma diagnosis is a Lung Function Test, which is also called a Pulmonary Function Test or PFT. This is the test where you wear the little nose clips to plug your nose and blow into a mouthpiece that is attached to a machine and you are coached by a respiratory therapist (like me!) how to do different breathing maneuvers. The most common maneuver is the spirometry where you take a deep breath in and blow out hard & fast like you are blowing out an entire birthday cake full of candles. This specific maneuver and result is important in diagnosing asthma along with your medical history etc.

Response from John Bottrell, RRT

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This is a great question. I think the answer to this question will vary based on who answers it. I was diagnosed when I was two-years old. And this was way back in 1972. I did ask my mom about this a few years ago, and she had no memory of how I was diagnosed, just that I was. So, at that time, I doubt there were any tests done. And I'm speculating here. But, I think I can speculate with some degree of accuracy.

Interestingly, many experts say you cannot diagnose asthma prior to the age of 5 because small children cannot do the required testing. But, that's not necessarily true. Doctors often use experience guided by common sense to diagnose asthma even in small children without doing any specific tests. This is essential, because it allows them to effectively treat small asthmatics. Doctors can diagnose asthma if you present with obvious asthma symptoms. Mom said I always seemed to have a cold, and I was always breathing heavy. I probably also had wheezes and signs and symptoms of asthma that made it easy for my doctors to recognize it and diagnose asthma.

You can diagnose it based on a positive response to asthma medicines. Back then I responded well to theophylline and epinephrine. You can also diagnose based on family history. I don't think this was the case with me, although I did have a great uncle who had severe asthma when he was a small child. So, for me, in my case, there was no testing done, at least that I'm aware of.

But, I can say that testing was done when I was 15. By this point, my asthma became very severe and uncontrolled. My doctors had me undergo a series of tests just to make sure that I really did have asthma. One such test was a pulmonary function test. I also underwent a differential diagnosis. This means I was tested for other diseases that might mimic asthma to make sure I didn't have them. This is important because these other diseases are treated differently than how asthma is treated. For instance, a sweat test may rule in or rule out cystic fibrosis. An EKG may rule in or rule out heart issues. A pH probe may rule in or rule out GERD. For me, these tests ruled out these other diseases and ruled in asthma. But, in my case, we already knew I had asthma. Still, it was necessary so my doctors could continue treating me with the best approach.

How was your asthma diagnosed?

What asthma diagnostic tests were used? Share in the comments below!

Editor's Note: The information in this article cannot be substituted for medical advice. Always consult your doctor before beginning, ending, or changing treatments.

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