Updated: November 24, 2017
Diagnosis of asthma can be done by taking a thorough medical history and performing breathing tests to measure how well your lungs work.
Your doctor will do a physical exam and ask you questions about your signs and symptoms and about any other health problems to rule out other possible conditions such as a respiratory infection or chronic obstructive pulmonary disease (COPD).
Lung or pulmonary function tests can be done to determine how much air moves in and out as you breathe. These tests may include:
This test is done to determine the narrowing of your bronchial tubes by checking how much air you can exhale after a deep breath and how fast you can breathe out.
A peak flow meter is a simple device that measures how hard you can breathe out. If the peak flow readings are lower than usual, your lungs may not be working properly and your asthma may be getting worse.
Usually lung function tests are done before and after taking a medication called a bronchodilator such as albuterol, to open your airways. If your lung function improves with use of a bronchodilator, it is likely that you have asthma.
Methacholine is a asthma trigger that will cause mild constriction of your airways, when inhaled . If you react to the methacholine, you are likely to have asthma. Even if your initial lung function test is normal, this test should be done.
When your airways are inflamed, you may have higher than normal nitric oxide levels in your breath which can be measured by this test.
This can be performed by a skin test or blood test which will identify allergy to pets, dust, mold and pollen.
While you cough, the discharge which is a mixture of saliva and mucus (sputum) will have certain white blood cells (eosinophils). Eosinophils are present when symptoms develop and become visible when stained with a rose-colored dye (eosin).
Any structural abnormalities or diseases such as infection that can cause or aggravate breathing problems can be identified by a chest X-ray and high-resolution computerized tomography (CT) scan of your lungs and sinuses.
Your airway obstruction can be measured before and after you perform vigorous physical activity or take several breaths of cold air.
Asthma is classified into four general categories depending on the severity, signs and symptoms.
It will have mild symptoms up to two days a week and up to two nights a month.
Symptoms will occur more than twice a week, but no more than once in a single day.
In this case you will have symptoms once a day and more than one night a week.
Symptoms occur throughout the day on most days and frequently at night.
Asthma complications include:
Both short-term and long-term complications caused by asthma can be prevented by proper treatment.