Evaluation of an Asthma Treatment Strategy Based on Exhaled Nitric Oxide Measurements in Adolescents

Inclusion Criteria: * Clinical diagnosis of asthma made by a doctor over a year prior to study entry OR symptoms have been present more than a year if the diagnosis was made less than a year prior to study entry * Have symptoms consistent with persistent asthma OR have evidence of uncontrolled disease. More information on this criterion can be found in the DAIT ICAC-01 protocol. * Currently reside in a pre-selected area containing at least 20% of households below the U.S. government poverty level * Do not smoke and have not used smokeless tobacco products in the year prior to study entry * Able to perform eNO measurement procedures and spirometry at study screening * Parent or guardian willing to provide informed consent, if applicable * History of clinical varicella (chicken pox) or have received varicella vaccine * Planning to stay in the area for the next 12 months * Primary language is English. Spanish speakers may enroll at centers with Spanish-speaking staff. * Parent or guardian primarily speaks English (or Spanish at centers with Spanish-speaking staff), for participants with parent or guardian providing informed consent * Willing to allow the study physician to manage disease for the duration of the study * Willing to change asthma medications in order to follow the protocol Exclusion Criteria: * Adherence to controller medication between Visits 1 and 2 is less than 25%. More information on this criterion can be found in the DAIT ICAC-01 protocol. * Determined to have mild intermittent asthma at Visit 1 * Have had a life-threatening asthma exacerbation requiring intubation, mechanical ventilation, or resulting in a hypoxic seizure in the 5 years prior to study entry * Have significant medical illnesses other than asthma. More information on this criterion can be found in the DAIT ICAC-01 protocol. * Unable to use a metered-dose inhaler for administration of a beta-agonist rescue medication or a dry powder inhaler for the administration of asthma controller regimens * Known hypersensitivity to any medications commonly used for the treatment of asthma * Have not completed a home evaluation within 4 weeks of study screening * Currently participating in another asthma-related drug or intervention study, or have participated in another asthma-related drug or intervention study in the month prior to study entry * Does not sleep at least 4 nights per week in one home * Lives with a foster parent (not applicable if patient is able to provide informed consent) * Does not have access to a phone * Requires certain medications. More information on this criterion can be found in the DAIT ICAC-01 protocol. * Urine cotinine level above 100 ng/ml at study screening * Pregnant or breastfeeding