Asthma Challenge Tests
If you do not have any symptoms in-between two episodes of asthma, the test results may not help your doctor make an accurate diagnosis of asthma. Thus, it may be difficult to confirm and treat the disease. This is when asthma challenge tests are recommended to confirm asthma. It is meant for adults, not children.
There are two types of challenge tests: (a) inhalation challenge and (b) exercise challenge. Inhalation challenge test involves inhaling small amounts of substances that can cause reactions in the airways and then doing a spirometry. In case there is no reaction, the amount of the allergen is increased and the breath test repeated. This process is repeated till the lung functions decrease by about twenty per cent.
Exercise challenge test involves doing spirometry before, during and after an exercise such as treadmill or riding a stationary bicycle in a laboratory. If the peak flow decreases by more than twelve per cent, exercise induced asthma is diagnosed. It is important to remember that the reactions of asthma challenge tests may be very strong and you may need emergency asthma treatment. Occasionally, the reactions may be delayed. This is why asthma challenge tests are normally done in a hospital setting by a trained physician. You may need to be in the hospital for one day just in case there is a delayed reaction.