Testing Of Lung Capacity By Asthma Specialists


Testing of lung capacity is commonly done by asthma specialists to detect the severity of asthma. The asthma patient is asked to breathe into a closed tube connected to a machine that measures speed at which he can expel the air from lungs and the total volume of air that is expelled. In many asthma patients there may not be any abnormalities in amount of air expelled. It means that their lung volume is perfect but there are obstructions in their bronchial tubes. This bronchial obstruction prevents air from being exhaled at the normal rate of speed which could be an indication of asthma.


The patient is made to undergo lung function test and if the first set of breathing tests show abnormal results then the patient  will be asked to inhale a bronchodilator drug and repeat the test. If the second set of tests show more than 20 percent im­provement in the rate of exhalation of air then the patient is normally diagnosed with asthma.


Machines that measure such lung functions range from relatively inexpensive devices, called spirometers, to very sophisticated high-tech computers that record complete lung functioning. Most asthma specialists have some type of breathing machine to diagnose and follow the progress of their patients with asthma.

Nowadays a type portable hand held devise known as Peak Flow meter is used to monitor air flow through the bronchial tubes in lungs. With Peak Flow Meter it is now possible for people with asthma to monitor their own lung functions at home itself. These meters are very helpful in recognizing the different stages of an asthma attack and determining what substances in the home or workplace are trigger­ing asthma.


Most doctors and asthma specialist now recommend Peak Flow Meter to their patients. They believe that people who have asthma can benefit from the use of a peak flow meter. An asthmatic can adjust his daily medication by monitoring his progress with a peak flow meter. No effective asthma management plan is now complete without peak flow meter. However peak flow meter will not be of much use to those with mild asthma it will help only those with acute or chronic asthma and those who need to take daily medications.

When your medical history, physical exam, and lab tests point to allergies as the major reason in your asthma, skin testing is usually done. There are different types of skin test: the prick or puncture test, the scratch test, and the intradermal test. In the prick test, the test allergen is placed on top of the skin, and the skin is pricked through the drop. In the scratch test, the skin in lightly scratched and a drop of the test allergen is placed onto the scratched area. In the intradermal test, allergen is injected beneath the skin with a very small needle. The weaker scratch or prick tests are usually done first to minimize the chances of triggering an allergic reac­tion. If these tests are negative, a stronger intradermal test is administered.


If you are allergic to any of the test allergens a wheal-and-flare reaction will develop at the test site. The flare is the redness. The wheal is the white center in the middle of the redness. In practice an urticaria or hive is produced, and the size of the urticaria can be anything from 2mm onwards. The higher the size of the hive means higher sensitivity to the testing substance.


Skin tests are most helpful in identifying an allergy to inhaled substances such as house dust mites, molds, pollens, or animal saliva or dander. It will clearly show which type of allergens are playing a role in your asthma. Though skin test methodology has not changed since decades these are very valuable and accurate ways to determine the presence of allergies. They are inexpensive and are very safe when carried out under the supervision of a physician who is knowledgeable in allergy skin testing. Skin test results are available within an hour after the tests are applied.


It is also possible to detect allergies with blood tests. In these tests a small sample of blood is processed through an analyzer to see if the blood con­tains allergic IgE antibodies to certain allergens. These tests are very helpful when the doctor cannot perform skin tests because of a skin eruption or a patient’s fear of needles or when there is a chance of inducing an allergic reaction with skin tests.  However allergy blood tests are not considered as accurate as skin tests. Finally it all depends on the doctor and the allergy specialist to interpret the results and correlate with patient’s medical history to arrive at the exact allergens that trigger asthma.







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