Sputum: stains, cx Bacterial, TB, pneumocystis, fungal TB skin test TB Neck radiograph, AP/lateral Tracheitis, abscess, foreign body Adolescents Not necessary for the diagnosis of croup Relative contraindication if unstable airway Consider portable if unstable Chest radiograph AP/lateral Lower respiratory disease, atelectasis, foreign body, barotrauma, effusion, mass, chest wall trauma/deformity, cardiac process Forced expiratory or Foreign body Air trapping distal to bilateral decubitus foreign body Unilateral decubitus Distinguish effusion Effusion layers from infiltrate Abdominal radiograph, Abdominal mass, supine/prone, cross-table obstruction, lateral, upright) perforation Fluoroscopy Upper airway obstruction; structural or functional anatomic, foreign body, paralysis vocal cords, diaphragm Laryngoscopy/bronchoscopy Upper or lower airway Esophagoscopy for obstruction; structural esophageal or functional, foreign processes body Head CT scan Intracranial bleed, mass,