A Study to Explore the Utility of Fractional Exhaled Nitric Oxide (FeNO) Compared With Methacholine Challenge (MCC) Testing in the Assessment of Patients With Suspected But Undiagnosed Asthma

INTRODUCTION Overview: The measurement of exhaled nitric oxide (FeNO) is the only clinical test for measuring airway inflammation that can be performed consistently and accurately in clinical practice at the point-of-care. Airway inflammation is now recognized as the central mechanism in the pathogenesis of asthma. The measurement of FeNO with the NIOX MINO® device provides a rapid, noninvasive, and inexpensive tool to assess airway inflammation in inflammatory airway diseases such as asthma. The test is easy to perform and requires minimal training for the operator to conduct the test. Role of Exhaled Nitric Oxide (FeNO): FeNO has evolved as a predictive and prognostic biomarker for airway inflammation. Nitric oxide (NO) gas is produced in the epithelial cells of the bronchial wall as an intrinsic part of the inflammatory process. Measuring the amount of FeNO is useful in the initial assessment of patients with chronic cough or non-specific respiratory symptoms suggestive of asthma, and for the management of patients with established asthma who are receiving corticosteroid treatment. Intended Use: NIOX MINO® measures Nitric Oxide (NO) in human breath. Nitric Oxide is frequently increased in inflammatory processes such as asthma. The fractional NO concentration in expired breath (FeNO) can be measured by NIOX MINO® with assurance that such measurements are repeatable and according to guidelines for NO measurement established by the American Thoracic Society. Rationale for Study: The burden of asthma in the U.S. is significant and growing. In addition, it has been established that asthma is both over- and under- diagnosed. Equally concerning is the fact that nearly 75% of these misdiagnosed patients are receiving anti-asthma treatments. Data such as these point out the need for a simple, inexpensive and reliable way to establish the diagnosis of asthma. Presently, the assessment of patients with suspected but undiagnosed asthma is to perform Methacholine Challenge (MCC) testing to evaluate airway hyperresponsiveness. However, MCC, testing is difficult, time-consuming, and costly and also involves some level of risk to the patient. Nonetheless, there is some evidence that FeNO testing may be able to identify the patients who actually have asthma among those with suspected but undiagnosed asthma who have normal pulmonary function tests, thus potentially eliminating the need for MCC testing in many patients. CLINICAL INVESTIGATION OBJECTIVES To explore the utility of FeNO compared with MCC in assessing patients with suspected but undiagnosed asthma. CLINICAL INVESTIGATION PLAN This is an exploratory, multi-center, single-visit, outpatient study. Approximately 50 subjects will participate in the study during an (approximately 8-16 week study enrollment period: * Demographics * Physical Characteristics * Smoking history (cigarettes only) * FeNO * Spirometry * Asthma and Allergy Specialists MCC Test Procedure Subject discharge from the study: Once all information has been collected and all procedures have been performed, the subject will be discharged from the clinic and their study participation will be complete Medical device: The NIOX MINO® was initially cleared by the FDA on March 4, 2008 as a new hand-held device for the measurement of exhaled Nitric Oxide, a marker of eosinophilic airway inflammation. The most recent clearance by the FDA was on September 2, 2010 for Instrument (09-1100), which will be used in this study. NIOX MINO® can be used in children 7-17 years of age and in adults 18 years of age or older in the initial assessment and management of asthma. The NIOX MINO® is a 10 second test based on exhaled breath measured at a 50 ml/second flow rate. Results are provided at the point of care within 2 minutes after the successful completion of the breath test. The test cannot be influenced by patient effort or variations in the clinician's test technique. Definitions: Adverse event: Any incident where the use of a medical device (including in vitro diagnostics) is suspected to have resulted in an adverse outcome in a patient. Serious Injury means injury or illness that: * Is life-threatening * Results in permanent impairment of a body function or permanent damage to a body structure, or * Necessitates medical or surgical intervention to preclude permanent impairment of a body function or permanent damage to a body structure. Malfunction: the failure of a device to meet its performance specifications or otherwise perform as intended. Caused or contributed: the death or serous injury was or may have been attributed to a medical device, or that the medical device was or may have been a factor in a death or serious injury, including events occurring as a result of: * Failure * Malfunction * Improper or inadequate design * Manufacture * Labeling * User error