• Pulmonary function test. Measures how much air the lungs can hold and how quickly it is exhaled.
  
  
• Bronchoprovocation test. Involves inducing a minor asthma attack to diagnose asthma when symptoms are not present. Most bronchoprovocation tests use histamine or methacholine but may include specific agents, such as food additives or environmental allergens.
  
  
• Spirometry. Measures how much air a person blows out in a specific period of time, and how forcefully it is blown. It can reveal the extent of airway obstruction present, and how much of the obstruction is reversible.
  
  

  

• Pulse oximetry. Measures the amount of oxygen in a person’s bloodstream using a probe placed on a fingertip.
  
  
• Chest x-ray. Produces an image of the chest using low doses of radiation. This test can be useful in detecting air trapped in the lungs. It may also be used to rule out other conditions and diseases known to cause symptoms similar to asthma.
  
  
• Allergy skin testing. Identifies a specific allergen that might be triggering asthma attacks. While allergies are a separate condition from asthma, allergic reactions often trigger attacks in asthmatics. A small amount of the allergen is introduced to the skin (through a prick, scratch, patch or injection), and a hive will indicate that an allergy to the substance is present. It is not 100 percent accurate, but can be an effective tool in diagnosing allergy triggers.
  

  

• Allergy blood tests. Measures the amount of specific immunoglobulin E (IgE) produced to an individual allergen in a sample of blood. The most commonly used blood test for allergy related conditions is the radioallergosorbent test (RAST). This test looks for the presence of allergy-specific IgE in the bloodstream. During an allergic reaction, the body produces IgE antibodies to protect against what it mistakenly perceives to be a dangerous substance. The level of IgE correlates to the sensitivity a patient has to the allergen.

Because of the nature of EIA, a physician also may test the patient’s breathing during exercise. During these tests, a patient will use a treadmill or stationary bike. The patient’s breathing will be tested at rest, after six to eight minutes of exercise and then at regular intervals. The last test will come at least 30 minutes after the patient has finished activity. By examining the results, a physician can determine how exercise affects the patient’s breathing ability.

Even when exercise-induced asthma is suspected, a physician will want to rule out other potentially more serious conditions before proceeding with treatment. For example, shortness of breath during exercise could be related to an underlying heart condition, poor athletic conditioning or pulmonary problems rather than asthma. In such cases, a physician may want to perform an echocardiogram to rule out potential heart ailments or other conditions. Also known simply as an “echo,” an echocardiogram is a common diagnostic test that uses sound waves to create pictures of the heart and its vessels.