How Is Asthma Diagnosed?

Some things your doctor will ask about include:

• Periods of coughing, wheezing, shortness of breath, or chest tightness that come on suddenly, occur often, or seem to happen during certain times of the year or season
• Colds that seem to “go to the chest” or take more than 10 days to get over
• Medicines you may have used to help your breathing
• Your family history of asthma and allergies
• Things that seem to cause your symptoms or make them worse

Your doctor will listen to your breathing and look for signs of asthma or allergies.

Your doctor will probably use a device called a spirometer (speh-ROM-et-er) to check how your lungs are working. This test is called spirometry (speh-ROM-eh-tree). The test measures how much air you can blow out of your lungs after taking a deep breath, and how fast you can do it . The results will be lower than normal if your airways are inflamed and narrowed, or if the muscles around your airways have tightened up.

As part of the test, your doctor may give you a medicine that helps open narrowed airways to see if the medicine changes or improves your test results.

Spirometry is also used to check your asthma over time to see how you are doing.

Spirometry usually cannot be used in children younger than 5 years. If your child is younger than 5 years, the doctor may decide to try medicine for a while to see if the child’s symptoms get better.

If your spirometry results are normal but you have asthma symptoms, your doctor will probably want you to have other tests to see what else could be causing your symptoms.

These include:

• Allergy testing to find out if and what allergens affect you.
• A test in which you use a peak flow meter every day for 1-2 weeks to check your breathing. A peak flow meter is a hand-held device that helps you monitor how well you are breathing.
• A test to see how your airways react to exercise.
• Tests to see if you have gastroesophageal reflux disease.
• A test to see if you have sinus disease.

Other tests, such as a chest x ray or an electrocardiogram, may be needed to find out if a foreign object or other lung diseases or heart disease could be causing your symptoms. A correct diagnosis is important because asthma is treated differently from other diseases with similar symptoms.

Depending on the results of your physical exam, medical history, and lung function tests, your doctor can determine how severe your asthma is. This is important because the severity of your asthma will determine how your asthma should be treated. One way for doctors to classify asthma severity is by considering how often you have symptoms when you are not taking any medicine or when your asthma is not well controlled.

Based on symptoms, the four levels of asthma severity are:

• Mild intermittent (comes and goes)—you have episodes of asthma symptoms twice a week or less, and you are bothered by symptoms at night twice a month or less; between episodes, however, you have no symptoms and your lung function is normal.
• Mild persistent asthma—you have asthma symptoms more than twice a week, but no more than once in a single day. You are bothered by symptoms at night more than twice a month. You may have asthma attacks that affect your activity.
• Moderate persistent asthma—you have asthma symptoms every day, and you are bothered by nighttime symptoms more than once a week. Asthma attacks may affect your activity.
• Severe persistent asthma—you have symptoms throughout the day on most days, and you are bothered by nighttime symptoms often. In severe asthma, your physical activity is likely to be limited.

Anyone with asthma can have a severe attack—even people who have intermittent or mild persistent asthma.