The purpose of this prospective study is to evaluate the efficacy of the ResAppDx software application in diagnosis of pneumonia and other respiratory conditions (bronchiolitis, asthma/reactive airway disease, croup, upper or lower respiratory tract infections) in infants and children. Patient's cough sounds will be recorded using a smartphone and analysed using the ResAppDx software. The ResAppDx diagnosis will be compared to radiologic diagnosis and/or clinical diagnosis. The ResAppDx diagnosis will not be provided to the clinician or patient.

Inclusion Criteria:

• Infant or child aged 29 days - 12 years
• Presenting to the study site with signs or symptoms of respiratory disease including cough, wheezing, stridor, chest in-drawing/retractions, difficulty breathing, fast breathing, abnormal lung sounds on exam, cyanosis/hypoxemia.
• Coughing spontaneously or able to cough voluntarily

Exclusion Criteria:

• Lack of a signed consent form from parent or legal guardian
• Lack of signed assent form for children aged 7 years or older who, in the opinion of the investigator, is able to provide assent based on their age, maturity or psychological state.
• Need for mechanical ventilatory support (including invasive, continuous positive airway pressure, or bilevel positive airway pressure) or high flow nasal cannula
• Any medical contraindication to voluntary cough, including (only enrolled if coughing spontaneously): severe respiratory distress, history of pneumothorax, eye/chest/abdominal surgery in past 3 months, hemoptysis in the past month, or too medically unstable to participate in study per treating clinician.
• Subject previously enrolled
• Tracheostomy present or tube placed

Patients with signs or symptoms of respiratory disease presenting to participating Emergency Departments, Urgent Care Clinics, Primary Care Clinics