Additional tests: Ruling out conditions other than asthma

If your doctor suspects that you have a condition in addition to or other than asthma, you may need tests such as:

• X-ray or computerized tomography (CT) imaging of your chest
• CT scans of your sinuses
• Blood tests
• Gastroesophageal reflux assessment
• Examination of the phlegm in your lungs (sputum induction and examination) for signs of a viral or bacterial infection

Your doctor may also want to see whether you have other conditions that often accompany asthma and can worsen symptoms. These include:

• Heartburn (also known as gastroesophageal reflux disease or GERD)
• Hay fever
• Sinusitis

Your doctor may also perform allergy tests. These can be skin tests, blood tests or both. Although not used to diagnose asthma, allergy tests can help identify an allergic condition, such as hay fever, that may be causing your symptoms or worsening existing asthma.

Sometimes, diagnosing the cause of breathing problems is a challenge. It can be difficult to differentiate asthma from other conditions — particularly in young children.

When asthma coexists with another condition that affects breathing, it can further complicate diagnosis.

Even if a diagnosis isn't certain, your doctor may prescribe medications or other treatment to see what helps. It may take time — and patience — to get the correct diagnosis and determine the best course of treatment.