Oxidative stress is seen in children with asthma, but is hard to measure. The investigators exploring the utility of using a commercially available assay to measure oxidative stress in the urine in asthmatics. Additionally, the investigators will attempt to prove that oxidative stress is higher in children with acute asthma compared to those with stable asthma and that this stress is also higher in children with more severe clinical asthma exacerbations compared to less severe ones.

Inclusion Criteria:

Group 1

1. Patients aged 4-18 years
2. Known stable asthmatics on no medications or with no medication changes in 3 weeks prior to enrollment
3. No asthma hospitalizations in past 3 months
4. Parent available to consent

Group 2

1. Patients aged 4-18
2. Known asthmatic, admitted to Stony Brook University Hospital for status asthmaticus
3. Parent available to consent

Exclusion Criteria:

1. Any child with documented fever within 24 hours of study entry
2. Any child with a known current history of tracheo- or bronchomalacia
3. Any child with known clinical or laboratory evidence of shock (see below)
4. Any child with history of documented immunodeficiency, rheumatologic disease, cystic fibrosis, or renal dysfunction (see below)
5. Any child with a current or recent (less than 1 year) history of tracheostomy
6. Any child with a known genetic abnormality
7. Any pregnant child
8. Any child with a history of autism
9. Any child whose parent/caregiver is unable to give informed consent

Group 1:

25 subjects will be recruited from among the children seen at the Stony Brook University Pediatric Pulmonary and Allergy Clinic.

Group 2 25 subjects will be recruited from among the children admitted to Stony Brook University Hospital with a diagnosis of acute asthma exacerbation or reactive airway disease from Monday at 12 AM to Friday at 5 PM.