How Doctors Determine an Asthma Diagnosis

You're wheezing, coughing, and short of breath—could it really be asthma? If your doctor suspects that you have this chronic condition, you'll need to undergo some testing to find out if this chronic condition is the cause of your distress.

Your risk for having asthma can increase because of the following:

  • Allergies
  • Eczema
  • Hives
  • Having a family history of asthma
  • Smoking
  • Being exposed to second-hand smoke

Types of Tests for an Asthma Diagnosis

Firstly, the doctor will have you take a physical exam and she'll review your personal and family medical history. She'll also listen to your lungs for wheezing, especially when you breathe out, since this is a classic sign of asthma. In addition, you can expect her to perform some (or all) of the following types of lung function tests to make a formal asthma diagnosis:

  • Spirometry measures the amount of air you're able to breathe in and breathe out, as well as how much air you can force out in a one-second period. If your readings are low, your doctor may ask you to use a fast-acting relief inhaler and repeat the test. In people with asthma, the medication should help open the airways and improve the results.
  • Nitric Oxide Tests are relatively new and aren't widely available yet. It measures the nitric oxide levels in the air you breathe out. When the levels are high, this can be a sign of airway inflammation, which can be caused by asthma.
  • A Challenge Test consists of a substance you inhale that can cause your airways to become obstructed. After this test, you'll undergo another spirometry test. Afterwards, you'll be asked to use a fast-acting relief inhaler, then repeat the challenge test again to see if the results improve, as they should if you have asthma.
  • Allergy Tests can also be helpful for people who may have allergic asthma. They help identify your allergy triggers so you can determine how best to avoid them. In addition, blood tests and a chest X-ray can help to narrow in on what's causing your symptoms.

Ruling Out Other Conditions

When an asthma diagnosis isn't clear and you need to consider other causes for your discomfort, your doctor may want to explore other health problems that can appear similar to asthma:

  • Respiratory infection
  • Bronchitis
  • Pneumonia
  • Blood clot in your lung
  • Other airway obstruction
  • Chronic obstructive pulmonary disease (COPD)

Managing Your Condition

If your doctor confirms that you do have asthma, he will most likely work with you to identify your triggers and come up with an asthma action plan to help you effectively manage the condition, often using a combination of control medications and a fast-acting relief inhaler. 

"Asthma Diagnosis." American College of Allergy, Asthma and Immunology. ACAAI, n.d. Web. 20 June 2011.

"Asthma: Risk Factors." Mayo Clinic. Mayo Foundation for Medical Education and Research, 27 May 2010. Web. 22 June 2011.

"Asthma: Steps in Testing and Diagnosis." Mayo Clinic. Mayo Foundation for Education and Research, 24 June 2009. Web. 20 June 2011.

"How is Asthma Diagnosed?" National Heart, Lung, and Blood Institute. US Dept. of Health and Human Services, n.d. Web. 20 June 2011.