To make an asthma diagnosis, doctors rely on several things -- one important one is diagnostic testing for asthma. The results of certain asthma tests, along with family medical history and physical examination, will help a doctor make an accurate asthma diagnosis. What asthma tests might your doctor order?
Explore the various forms of asthma diagnostic testing.
Pulmonary Function Testing
Doctors often order pulmonary function testing (PFTs) for people who have persistent asthma. PFTs, such as spirometry and others, measure different aspects of how the lungs are functioning, give the doctor a better sense of the severity of the asthma and tell how well asthma treatment is working.Most PFTs are performed in a pulmonary function laboratory. The person being tested will be asked to breathe into a special mouthpiece. Each measurement is done multiple times to make sure the results are consistent. Tests include spirometry (see below), lung volumes & diffusion capacity.
Spirometry
A.D.A.M.
Spirometry is a type of pulmonary function test used in diagnosing asthma. It measures how well the lungs are working. The findings from this test are not enough to prove a person has asthma, but they can help narrow down an asthma diagnosis.
Spirometry measures the maximum amount of air that is exhaled forcibly after deep inhalation. Abnormal findings suggest an airflow obstruction. Spirometry can also reveal signs that the obstruction is reversible. These 2 factors together suggest an asthma diagnosis.
Spirometry measures the maximum amount of air that is exhaled forcibly after deep inhalation. Abnormal findings suggest an airflow obstruction. Spirometry can also reveal signs that the obstruction is reversible. These 2 factors together suggest an asthma diagnosis.
Chest X-Ray
One of the less common forms of diagnostic testing for asthma, chest x-rays may help a doctor determine if other conditions of the lungs, heart or chest are present.A chest x-ray may also be ordered when a patient with asthma is hospitalized (as part of a preoperative physical exam) or treated in the ER because of a severe asthma attack. Asthma patients who also have symptoms suggesting other lung problems or heart disease may get chest x-rays as part of their annual exams.
During a chest x-ray, a special camera emits a small dose of radiation that is primarily absorbed by the bones. The x-ray enables a doctor to clearly see the lungs, heart, and bones of the chest, and determine if there is anything of concern.
Methacholine Challenge (Bronchoprovocation)
A methacholine challenge test can help with the diagnosis of asthma, although this test is rarely done. The other name it goes by, bronchoprovocation, means "provoking" or challenging the bronchial airways. This is done with methacholine, histamine, cold air or exercise.The purpose of the test is to see if the airways narrow in response to the substance or situation used to challenge them. This is known as hyperresponsiveness, and it is a key feature of asthma. If the methacholine challenge does not produce hyperresponsiveness, then asthma is unlikely.
Allergy Testing and Asthma
Allergy testing may be recommended for people with asthma, because allergies can play a significant role in causing asthma symptoms. Skin tests, blood tests and elimination diets are the most common and effective ways to diagnose allergies and allergic asthma.Approximately 20% of adults and children in the United States have allergies. Children are more susceptible to allergic reactions than adults, and approximately 80% of children with asthma also suffer from allergies.
