How is asthma diagnosed?

To diagnose asthma and distinguish it from other lung disorders, physicians rely on a combination of medical history, physical examination, and laboratory tests, which may include the following:

• spirometry - a spirometer is a device used by your physician that assesses lung function. Spirometry, the evaluation of lung function with a spirometer, is one of the simplest, most common pulmonary function tests and may be necessary for any/all of the following reasons:
  
  
  • to determine how well the lungs receive, hold, and utilize air
  • to monitor a lung disease
  • to monitor the effectiveness of treatment
  • to determine the severity of a lung disease
  • to determine whether the lung disease is restrictive (decreased airflow) or obstructive (disruption of airflow)
• peak flow monitoring (PFM) - a device used to measure the fastest speed in which a person can blow air out of the lungs. During an asthma or other respiratory flare up, the large airways in the lungs slowly begin to narrow. This will slow the speed of air leaving the lungs and can be measured by a PFM. This measurement is very important in evaluating how well or how poorly the disease is being controlled.
  
  
• chest x-rays - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
  
  
• blood tests - to analyze the amount of carbon dioxide and oxygen in the blood.
  
  
• allergy tests