Asthma diagnosis involves a number of procedures where the physician measures the air flow through the airways and the blood oxygenation.
Asthma is a lung disease where airway resistance shows an increase. The physician makes a diagnosis of asthma with the help of spirometry.
In particular, the forced vital capacity (FVC) and the forced expiratory volume in 1 second (FEV1 ) are important items to measure. A simpler home test is to measure the peak expiratory flow rate (PEF), which can be measured with a simple peak flow meter. The results are interpreted with the help of flow meter charts where sex and age is worked in.
Assessing pulmonary function
It is important for the doctor to assess the FEV1 /FVC ratio, as the size of the reduction of this is proportional to the severity of the asthma. The spirometry machine prints this out automatically. Also, if there is no reduction in this ratio, there might be another lung disease present (a restrictive airway problem, different from asthma). Using spirometry these flow-volume loops were recorded, which allow the lung specialist and the doctor to see how restrictive the airways are.
Other tests are X-rays, arterial blood gases and possibly CT and MRI scans in special cases that occasionally would be needed (see appropriate links in the table on Special procedures for lung diseases.
Allergy testing is another important aspect for patients with inhalation allergies or food allergies who have asthma. It may be that these patients should be on allergy shots, if the treating physician or the specialist feels that this would be helpful. Many asthma patients can be stabilized with allergy shots to the point where a stage IV asthma condition can convert into a stage II or III asthma, which will be a lot easier to control with medication from then on.
People who are sensitized to peanut protein can get anaphylactic reactions including asthma, even from traces of peanut products.
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