A number of other tests may be performed when asthma is suspected, primarily to rule out other potential causes of breathing problems, such as chronic obstructive pulmonary disease (COPD), pneumonia, bronchitis, pulmonary embolism and heart failure. Tests may also be performed to screen for a condition that commonly occurs in conjunction with asthma, such as gastroesophageal reflux disease (GERD), allergic rhinitis (hay fever) or rhinosinusitis. These tests may include:

• Chest x-ray. Uses low doses of radiation to produce an image of the chest.
  
  
• Sinus x-ray. Uses low doses of radiation to produce an image of the sinuses.
  
  
• Sputum examination. Uses a microscope to analyze a sample of sputum (phlegm coughed up from deep inside the lungs).
  
  
• Echocardiogram. Uses sound waves to create a picture of the heart.
  
  
• Electrocardiogram (EKG). Records the electrical activity of the heart.
  
  
• Stress test. Takes EKG readings of the heart while a person exercises.
  
  
• CAT scan of the chest. Creates a picture of the chest and upper abdomen.
  
  
• CBC (complete blood count). Determines the counts of various types of blood cells.
  
  
• Gastroesophageal reflux assessment. May include a number of diagnostic tests for GERD, including barium swallow (a test in which an x-ray is taken after liquid barium is ingested) and esophageal pH monitoring (involves passing a thin tube attached to a monitoring device through the nose and into the esophagus where it records the amount of stomach acid that reaches the esophagus).