Rapid Diagnostic Testing for Influenza
Information for Health Care Professionals
On this page:
- Background
- Reliability and Interpretation of Rapid Test Results
- Minimize False Results
- Influenza Diagnostic Table
Background
Rapid diagnostic tests for influenza can help in the diagnosis and management of patients who present with signs and symptoms compatible with influenza. They also are useful for helping to determine whether outbreaks of respiratory disease, such as in nursing homes and other settings, might be due to influenza.
- In general, rapid diagnostic testing for influenza should be done when the results will affect clinical decision making.
- Reliability and Interpretation of Rapid Test Results
Reliability and Interpretation of Rapid Test Results
The reliability of rapid diagnostic tests depends largely on the conditions under which they are used. Understanding some basic considerations can minimize being misled by false-positive or false-negative results.
- Sensitivities of rapid diagnostic tests are approximately 50-70% when compared with viral culture or reverse transcription polymerase chain reaction (RT-PCR), and specificities of rapid diagnostic tests for influenza are approximately 90-95%.
- False-positive (and true-negative) results are more likely to occur when disease prevalence in the community is low, which is generally at the beginning and end of the influenza seasons.
- False-negative (and true-positive) results are more likely to occur when disease prevalence is high in the community, which is typically at the height of the influenza season.
Minimize False Results
- Use rapid diagnostic tests with high sensitivity and specificity.
- Collect specimens as early in the illness as possible (within 4-5 days).
- Follow manufacturer’s instructions, including handling of specimens.
- Consider sending specimens for viral culture to confirm results of rapid tests especially when community prevalence of influenza is low and the rapid diagnostic test result is positive and when the rapid diagnostic test result is negative but disease prevalence is high. (Contact your local or state health department for information about influenza activity).
Additional Information
- State and Local Health Departments
- Association of Public Health Laboratories
- Weekly U.S. Influenza Activity Reports
- Clinician Outreach and Communication Activity
- Page last updated January 22, 2009