Common Tests or Labs to Diagnose Severe Persistent Asthma

There are several tests and labs used to make a proper diagnosis and monitor your ongoing condition. Below are listed the most common severe persistent asthma tests and labs ordered, why you need them, and what they can tell you about your condition.



Why Test?

What Happens?

Normal Result

Complete Blood Count IgE and Eosinophils are antibodies. If asthma is due to an allergy, the level of these antibodies will be raised. Regular blood test is performed; blood is drawn from venous puncture in arm Eosinophil : 1-4%

IgE – 4.2-595 U/mL

Sputum Sample To rule out other chronic illness like Tuberculosis Cough sputum into sterile specimen cup May show casts of small airways, thick mucoid sputum
Pulmonary Function Tests Measures the amount (volume) and/or speed (flow) of air that can be inhaled and exhaled in the lungs The patient performs several hard breathes into a machine Accurate measurement is dependent upon the patient’s performing the appropriate maneuver properly. Very difficult to perform in children.
Chest X-ray Rules out any other cause of blockage/narrowing of the bronchi This is a non-invasive test. A picture is taken of the chest and lungs. Increased bronchial wall markings, associated with chronic inflammation and accessory muscle use.