Asthma Diagnostic tests

Physical examination
to distinguish asthma from other possible diseases such as respiratory infections or chronic obstructive pulmonary disease (COPD) will ask you.
Tests to check your lung function
You may also have pulmonary function tests to determine how much air flows when you inhale and exhale.
These tests can include the following:
 • Spirometry. This test estimates the degree of narrowing of the airways by examining the amount of air expelled from the lungs after a deep breath and the rate of exhalation during exhalation
• Peak flow (maximum flow). A peak flowmeter is a simple device that measures how hard you are breathing.
If the number shown by the peak flowmeter is lower than normal, it indicates that your lungs are not working properly and your asthma has become more severe.
Your doctor will teach you how to work with the peak filometer device and the necessary measures when the maximum flow decreases.
Pulmonary function tests are often done before and after taking a bronchodilator such as albuterol to open the airways.
If your lung function improves after taking a bronchodilator, you may have asthma.
Other tests
Other tests to diagnose asthma include:
• Methacholine challenge.
Methacholine is known as an asthma stimulant, which when inhaled causes mild narrowing of the airways. If your body reacts to methacholine, you may have asthma. This test can be done even when your pulmonary function test results are normal.
• Nitric oxide test.
This test measures the amount of nitric oxide gas in your breath. Of course, this test is not very common and available. When your airways are inflamed (one of the symptoms of asthma), the amount of nitric oxide in your breath may be higher than normal.
• Imaging tests.
X-rays and CT scans of your lungs and nasal cavities (sinuses) can show any structural abnormalities or diseases (such as infections) that can cause or worsen breathing problems.
 • Allergy tests.
Allergy tests can be done through a skin test or a blood test. Allergy tests can show allergies to pets, pollen, fungi, and pollen. Diagnosing allergenic stimuli for asthma is important, and it is necessary to use allergen immunotherapy recommendations for the patient in these cases.
• Sputum eosinophils.
This test consists of examining a type of white blood cells (eosinophils) in a mixture of saliva and mucus (sputum) that comes out when you cough. Eosinophils appear when the symptoms of the disease appear and progress. Eosinophils are stained and identified using a red dye called eosin.
• Stimulus tests for exercise-induced asthma and cold-induced asthma.
In these tests, your doctor measures the degree of obstruction and narrowness of your airways before and after vigorous physical activity and several breaths in cold air.