1. Disclose Your Medical History
Your doctor will have to rule out a wide range of possible causes of your breathing difficulties, so you'll need to provide full disclosure of your or your child's medical history. The most common signs and symptoms of asthma are shared by other medical conditions, including emphysema, vocal cord malfunctions and congestive heart failure. You should expect that your doctor will consider these and other conditions as a possible cause, and conduct tests for them as well.
2. Measure Your Lung Function
In your doctor's office, you'll likely be introduced to one of two common tools used to measure lung function: the spirometer and the peak flow meter. A spirometer can gauge the extent to which your bronchial tubes narrow. During a spirometer test, you'll take a deep breath and the doctor will measure how quickly you can clear your lungs and compare the volume of air you exhaled against the amount you inhaled. You'll most commonly encounter peak flow meters in home settings, as they are used to anticipate impending attacks. However, they also double as an asthma screening tool. These devices measure the air flow going in and out of your lungs, and when readings start to decrease, it's a sign that you have constriction in your air passageways.
3. Take the Methacholine Bronchial Challenge
Should your doctor be unable to arrive at a definitive diagnosis using a spirometer or a peak flow meter, you might be asked to take a different kind of test called the methacholine bronchial challenge. Methacholine is a substance known to trigger mild asthma attacks in afflicted patients. Your doctor will ask you to inhale some, then check to see if your lungs respond by constricting. If so, asthma will become a strong suspect.
4. Classify Your Asthma
Depending on the results of your test, you or your child will be diagnosed with one of four major types of asthma. Mild intermittent asthma attacks only occasionally and has relatively mild symptoms. Mild persistent asthma occurs more frequently, but attacks are not serious in nature. Moderate persistent asthma requires much more careful treatment, and severe persistent asthma affects the patient throughout the day and night. You'll probably also be introduced to the terms "extrinsic" and "intrinsic" during the screening and diagnostic process. These are relatively new ways of classifying asthma. Extrinsic asthma is triggered by an irritant in the air, while intrinsic asthma originates within the body and can attack with or without the presence of an airborne trigger.
