What is Exhaled Nitric Oxide Test

The exhaled nitric oxide test for asthma is among the newer and lesser known asthma tests. Only some hospitals offer it so it is not very widely available and there are also some concerns that people have about its efficacy and use.

The exhaled nitric oxide test is one of the many that may be used to test the presence and severity of asthma in a person. As the name suggests this test measures the amount of nitric oxide present in one’s breath that can indicate airway inflammation – which is one of the unmistakable signs of asthma.

exhaled-nitric-oxide-testThough all of us produce some amount of nitric oxide, the levels of this gas in our exhalations is elevated when the airways are inflamed.

The test is usually administered to make adiagnosis of asthma or to measure the efficacy of asthma medications that a person may be on.

It is one way of determining how well controlled a person’s asthma is as well as a way to determine the type of medication that may work best for the person.

The test is usually administered by asking the person to exhale into a device that is later connected to an analyzer.

There are however concerns regarding this type of asthma testing – as to its efficacy and its usefulness as a diagnostic tool.

Limitations of the exhaled nitric oxide test

There are certain factors that limit the efficacy and use of this type of asthma testing according to some experts. Some experts are of the opinion that the test is not so useful for diagnosing asthma per se, as it is for ruling out bronchial asthma.

As yet the test is not standardized to the extent that its results are reliable enough to be acted upon.This is not a very widely accepted test since there can be a wide variation in what is considered ‘normal’ as regards levels of nitric oxide and degree of inflammation of the airways.

What can also make the test results go awry is the fact that there are other reasons why levels of nitric oxide may increase in one’s exhalations. For instance acidity in the airways can increase levels and in a sense offer a false positive.

A study conducted by Johan C. de Jongste, M.D., Ph.D., at the Erasmus University Medical Center-Sophia Children’s Hospital in the Netherlands and published in the American Journal of Respiratory andCritical Care Medicine, a publication of the American Thoracic Society also shed light on the acceptability and helpfulness of the Test.

The study found that the exhaled nitric oxide test is not of much use for children with asthma. The study looked at the impacts of daily monitoring of nitric oxide levels of children on improved and moreeffective medications. The researchers wanted to see if this offered better information than the simple monitoring of symptoms.

However it was found that whether the test was used or not did not make much of a difference to the improvement of symptoms. Researchers found however that regular monitoring of symptoms itself (with or without the nitric oxide test) was found to be very helpful.



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