COVID-19: Testing and surveillance

Who to Test (Persons Under Investigation)

  • Patients should be carefully evaluated to determine if they meet Persons Under Investigation (PUI) criteria
  • Due to a lack of available tests, non-PUI patients (including the worried well) should not have testing performed
  • Clinicians are strongly encouraged to test for other causes of respiratory illness (e.g. influenza, RSV)
    • In many systems, testing algorithms assume patients do not have COVID-19 if influenza or RSV positive
CDC PUI Guidance[1]

Your local PUI testing guidelines may be different, depending on test availability and local epidemiology; see state or local health departments and internal hospital resources

  • "Clinicians should use their judgment to determine if a patient has signs and symptoms compatible with COVID-19 and whether the patient should be tested."
  • Priorities for testing include:
    1. Optimize care for hospitalized patients and lessen risk of nosocomial infections
      • Hospitalized patients
      • Symptomatic healthcare workers
    2. Identify highest risk of complications
      • Symptomatic patients in long-term care facilities
      • Symptomatic patients ≥ 65 with symptoms
      • Symptomatic patients with chronic medical conditions and/or an immunocompromised state
      • Symptomatic first responders
    3. Decrease community spread
      • Symptomatic critical infrastructure workers
      • Healthcare workers and first responders
      • Any symptomatic individual
    4. Non-priority
      • Any individual without symptoms

Clinical Sample Collection[2]

Testing can be done in ambulatory setting if absolutely needed (see precautions)

  1. Upper respiratory tract specimen
    • Nasopharyngeal (NP) swab
      • Some systems allow sending both flu/RSV and COVID-19 test on the same swab to conserve testing supplies
  2. Additionally include lower tract specimen, if available
    • CDC does NOT recommend inducing sputum (because aerosol generating)
    • For productive cough patients: collect sputum
    • For patients for whom it is clinically indicated (e.g., those receiving invasive mechanical ventilation): collect lower respiratory tract aspirate or bronchoalveolar lavage sample
    • May include in same testing tube as upper respiratory track specimen (i.e. send as a single test) in some systems

See Also


  1. Criteria to Guide Evaluation and Laboratory Testing for COVID-19. Updated March 20, 2020.
  2. Interim Guidelines for Collecting, Handling, and Testing Clinical Specimens from Persons for Coronavirus Disease 2019 (COVID-19). March 19, 2020 Revision.