If you notice that you have trouble breathing periodically or you find yourself wheezing, especially at night or in the early morning, you may want to be tested for asthma. Since asthma occurs frequently in children, if you are a parent you should look for signs of breathing problems in your child and tell your doctor if they occur. You should be especially concerned if you or your child has risk factors for asthma like allergies or a family history of asthma. The symptoms of asthma can be scary. See a doctor as soon as possible if you or your child has an episode of difficult breathing that lasts more than a few minutes.

Asthma symptoms are often brought on or made worse by a “trigger.” A trigger can be an allergen (a substance you are allergic to) if you have allergies or some other factor like smoke, chemicals, stress, cold weather, or even (for women) menstrual cycles. If you notice that it becomes more difficult to breathe when you are exposed to certain triggers, you may want to see a doctor to be tested for asthma.

Diagnosing asthma

If you experience difficulty breathing or other asthma symptoms such as those mentioned above it is important to see a doctor. However, symptoms alone are not enough to diagnose asthma. Only a doctor can confirm that you have asthma and rule out other problems. An asthma diagnosis usually involves the following steps:

Medical History and Physical Exam

During your visit, the doctor will first ask you detailed questions about your health history, your family’s medical history and your symptoms. Then you will be given a physical exam. This will most likely involve listening to your lungs with a stethoscope and examining your nose and throat for signs of inflammation. The doctor may also ask to examine your body for signs of allergic conditions (such as eczema) on your skin.

Lung function tests

If your exam does not rule out asthma, the doctor will likely perform tests of your lung function. You cannot be diagnosed with asthma without showing signs of reduced lung function on one or more of these tests. Most lung function tests are non-invasive and can be performed in the doctor’s office using a medical instrument called a spirometer. Spirometry findings that indicate asthma are needed to make a definitive diagnosis of asthma. The spirometer records the amount of air you exhale and is used for two key lung function measurements:

• Forced vital capacity (FVC) is the maximum amount of air you can exhale after inhaling as deeply as possible. This is a measure of the total usable capacity of your lungs.
• Forced expiratory volume (FEV-1) is the maximum amount of air you can exhale in one second. This measures how well you can move air out of your lungs.

Your results on these tests will be compared to the expected values for someone of your age, height, and sex. If these numbers are lower than normal, there is reason to suspect you have asthma. Even so, your doctor may have you repeat the lung function tests after having you inhale a small amount of a drug that improves lung function in asthmatics by dilating the bronchioles. If your lung function numbers improve after inhaling the drug, you likely have asthma.

Even if your lung function tests are initially normal, the doctor may ask you to inhale a common trigger substance that tends to bring on asthma attacks in many asthmatics and then repeat the spirometry measurements. This is called a challenge test and if your lung function values decline after the challenge, it is likely that you have asthma.

Tests for exercise-induced asthma / bronchospasm

If your asthma symptoms occur only during exercise, your doctor may decide to give you an exercise challenge test (where you perform lung function tests at 5 minutes intervals while exercising in between) to make the diagnosis. If you do have exercise-induced bronchospasm, it shouldn’t interfere with your ability to be active and participate in vigorous exercise if you a have good asthma action plan.

Tests to rule out other problems

If your lung function tests indicate that you have reduced lung function, the doctor may want to do a few more tests to rule out other conditions that can cause similar symptoms as asthma. Some of these include: pneumonia, chronic obstructive pulmonary disease (COPD), tumors, congestive heart failure, and bronchitis. The tests to exclude these and other conditions may include a chest X-ray or CT scan of the lungs, a complete blood count (CBC), and an examination of respiratory mucus (sputum).

Allergy testing

If your doctor concludes that you do indeed have asthma, he or she may refer you to an allergy specialist to be tested for allergies. More than half of asthma cases are caused by allergic reactions in the lung airways, so allergy testing can help you determine the things that may trigger or worsen your asthma symptoms so you can avoid them in the future.

Asthma classifications
Based on the results from your tests, the doctor may give you a diagnosis of asthma with a specific classification. The classification is based on how severe and persistent your symptoms are. It can also help you better prepare for the symptoms you are likely to experience and provide a guide for treatment. The four main classifications of untreated asthma:

• Intermittent asthma is the mildest form of asthma, with symptoms up to twice a week.
• Mild persistent asthma is accompanied by symptoms more than twice a week, but no more than once in a single day.
• Moderate persistent asthma symptoms occur once a day.
• Severe persistent asthma is the most severe form, causing symptoms throughout the day on most days.

The classification of asthma is presently undergoing changes in the clinical and research communities. There is a new school of thought that asthma severity should be based on how severe the asthma is when it is controlled, or how much medical treatment it takes to control the symptoms. One new classification scheme from the Global Institute for Asthma uses the following classification of how well-controlled your symptoms are with medications:

• Controlled asthma means there are no daytime or nighttime symptoms, infrequent need for quick-relief medicines (no more than twice a week) and peak flow is normal with no asthma attacks.

• Partly controlled asthma involves daytime symptoms more than twice a week and sometimes at night with use of quick-relief medicine more than twice a week. Peak flow rate is less than 80 percent of your normal and asthma attacks occur at least once a year but not weekly.

• Uncontrolled asthma is when you have three or more of the features of partially controlled asthma at least 3 times a week, and asthma attacks are occurring weekly.