Diagnosis of Pneumonia in Immunocompromised Patients Chest x-ray Assessment of oxygenation Sputum induction or bronchoscopy to obtain lower respiratory samples Blood cultures Pathogens predicted based on symptoms, x-ray changes, and type of immunodeficiency Chest x-ray and assessment of oxygenation (usually by pulse oximetry) are done in immunocompromised patients with respiratory symptoms, signs, or fever.