Diagnosing Asthma

Diagnosing you or your loved one with asthma is a multi-step process ¹ that includes the use of medical histories, physical examinations, breathing and lung function tests, and other tests (when needed). Seek immediate medical attention if you or your loved one experiences frequent respiratory symptoms such as wheezing and shortness of breath or if your symptoms worsen.

Tests and Procedures

To diagnose asthma, your healthcare provider completes these steps and procedures: 

• Case history. A detailed case history gives your healthcare provider information about your symptoms, when they started, how often you experience them, your exposure to asthma triggers, and other relevant medical information. Your healthcare provider obtains this information through interviews, questionnaires, or observing you during your care visit. 
• Breathing tests. Breathing tests are common practice for diagnosing asthma. These tests measure the amount of air you can force from your lungs and nitric oxide levels ².
• Lung function tests. Lung function tests offer information about how your lungs work. They also help your provider identify any abnormalities with your lungs.
• Physical examination. Your healthcare provider will examine your body and listen to your breathing. These findings, along with your medical case history, breathing tests, and lung function tests, help diagnose your asthma. 
• Other tests. Your provider may ask you to complete allergy testing to determine if you have allergies that trigger your symptoms. Additionally, blood tests can provide your healthcare provider with information about the white blood cells from your immune system. There is a specific kind of asthma ³ caused by high levels of these white blood cells. 

Differentially Diagnosing Asthma

Diseases and conditions that resemble or mimic asthma can cause misdiagnoses or delay your asthma diagnosis. An accurate diagnosis is crucial for asthma control, management, and treatment. Thus, your healthcare provider must differentially diagnose asthma from these conditions.

What Is Differential Diagnosis?

Differential diagnosis is a process that helps your healthcare provider rule out conditions and diseases to provide you with an accurate diagnosis. During the differential diagnostic process, your provider considers other conditions and diseases that resemble asthma and uses the information obtained from your tests and procedures to rule out those conditions to get to asthma. Your provider takes these additional steps to differentially diagnose asthma:

• Chest x-rays. A chest x-ray provides a visual image of your chest and lungs.
• Swallow studies. Swallow studies are another imaging procedure that provide visual images of what happens when you swallow. Findings from a swallow study diagnose swallowing disorders, and help your provider rule out those disorders with symptoms that resemble asthma. 
• Refer you to a specialist. Information from specialists helps if your provider suspects or wants to rule out other diseases and conditions. 
• Bronchoscopy. A bronchoscopy ⁴ is a procedure that allows your healthcare provider to visually assess your airways for any injuries, obstruction, or blockages.