Strategies for Generating a Differential Diagnosis

Key points

  • Generating the differential diagnosis is a key step when first investigating an outbreak of unknown respiratory illness.
  • A thoughtful differential diagnosis ensures investigators consider all likely etiologies early in an outbreak investigation.
  • Resources are available to help generate a differential diagnosis.
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Differential diagnosis

One of the most important initial steps when investigating an outbreak of unknown respiratory illness is generating the "differential diagnosis."

The differential diagnosis is a list of the most likely infectious causes or etiologies of an outbreak. Differential diagnosis also refers to the process of comparing how likely one pathogen or etiology caused the disease versus another.

Generating a differential diagnosis enables investigators to use time and resources most efficiently and effectively to determine an outbreak's etiology.

The process helps focus:

  • Questionnaire development
  • Specimen collection
  • Laboratory testing
  • Empiric treatment regimens
  • Targeted urgent public health interventions

Also, a thoughtful differential diagnosis ensures investigators consider all likely etiologies early in an outbreak investigation. This process makes it less likely that investigators miss or overlook an etiology.

Pathogen spreadsheet

This spreadsheet on the principal pathogens or groups of infectious agents known to cause respiratory illness summarizes information on

  • Demographic data
  • Clinical information
  • Risk factors for disease

Persons with disabilities having problems accessing the above file may call 1-800-CDC-INFO (1-800-232-4636) for assistance.

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Content Source:
National Center for Immunization and Respiratory Diseases; Division of Bacterial Diseases