If an infant exhibits cyanosis, physicians may order any number of tests to help determine the cause of the condition. The diagnostic tests will vary depending on the type, nature and severity of symptoms. Such tests include:

• Chest x-ray to get an image of the heart's chambers, vessels and muscles.  This will also allow the physician to evaluate the lungs and any possibility that there is an associated with them.
  
  
• Electrocardiogram (EKG) to gauge the electrical activity of the heart.
  
  
• Echocardiogram to define the relationships, flows, function, dimensions, and dynamics of all valves, vessels, chambers, and septa.  This is considered the definitive test to evaluate a patient for possible heart disease. There is no recognized risk, radiation, or side-effect to an echocardiogram.. There are both fetal (performed in-utero) and infant echocardiograms available.
  
  
• Cardiac catheterization to determine if valve damage or abnormalities are present. During the cardiac catheterization, an angiogram may be done, in which a special dye (contrast medium) is injected into the blood vessels and chambers to view the activity, relationships, and size of vessel walls, valves and the heart muscle.
  
  
• Blood tests to assess for oxygen levels and other indicators of illness or medical conditions.