Update as of 2/8/18: The Centers for Disease Control and Prevention (CDC) has received reports of spot shortages of some influenza tests, including Rapid Influenza Diagnostic Tests (RIDTs) and Reverse Transcription-Polymerase Chain Reaction (RT-PCR). From the CDC:
- These reports coincide with an ongoing intense and widespread seasonal influenza epidemic, during which spot shortage of flu vaccines and influenza antiviral medications also have been observed.
- RIDTs are tests that can identify the presence of influenza A and B viral nucleoprotein antigens in respiratory specimens, and display the result.
- While RIDTs can be important for diagnosis and treatment, how well they work can vary dramatically based on a number of factors.
- Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and other molecular assays can identify the presence of influenza viral RNA in respiratory specimens.
- These test are generally much more reliable and are recommended by CDC for use on hospitalized patients.
- According to CDC guidance, testing is not needed for all patients with signs and symptoms of influenza to make antiviral treatment decisions.
- Once influenza activity has been documented in the community or geographic area, a clinical diagnosis of influenza can be made for outpatients with signs and symptoms consistent with suspected influenza, especially during periods of peak influenza activity in the community.
- Guidance for Clinicians on the Use of RT-PCR and Other Molecular Assays for Diagnosis of Influenza Virus Infection
- Guidance on the use of RIDTs
Information on this page pertains to healthcare settings including acute care hospitals, long-term care facilities (such as nursing homes and skilled nursing facilities), physicians’ offices, urgent care centers, and outpatient clinics. The recommendations and guidance may also be applicable to other settings where healthcare is delivered, such as school/work health clinics and home healthcare. Although assisted living facilities may not traditionally be thought of as healthcare facilities, the medical needs of the individuals who reside there sometimes necessitate special infection prevention precautions, so recommendations and resources for this setting are included in the long-term care section of this page. Guidance and recommendations for other settings such as daycare centers, businesses, and schools can be found here.
General Information for Healthcare Professionals
- Influenza Infection Control in Health Care Facilities (CDC) – summary documents, guidelines, and educational resources
- Seasonal Influenza Information for Healthcare Professionals (CDC)
- Respiratory Hygiene and Cough Etiquette (CDC)
To Prevent the Spread of Flu in Healthcare Facilities
Follow the CDC guidelines and recommendations for the prevention of seasonal influenza in healthcare settings:
Healthcare workers should:
- Implement droplet precautions for patients with influenza.
- Promote good respiratory hygiene practices.
- Instruct patients, visitors, and other healthcare workers to use a tissue to cover their nose and mouth when coughing or sneezing.
- Provide adequate supplies (tissues, face masks, trash cans, alcohol-based hand sanitizer).
- Encourage people in common areas who have respiratory symptoms to distance themselves (at least 3 feet) from others or wear a surgical mask, if they are able to tolerate it.
- Triage incoming patients and have a separate waiting area for patients with respiratory symptoms equipped with the necessary supplies (tissues, face masks, trash cans, alcohol-based hand sanitizer).
- Administer antiviral treatment and chemoprophylaxis to patients and healthcare personnel when appropriate.
- If sick with flu-like illness, stay home for at least 24 hours after fever has gone away (without the use of a fever-reducing medicine) and limit contact with other people.
- Facility administrators should:
- Encourage and administer seasonal influenza vaccine. Implement strategies to improve healthcare personnel influenza vaccination rates.
- Provide adequate tissues, face masks, and hand hygiene supplies for staff and in patient waiting areas and rooms.
- Monitor and manage ill healthcare workers.
- Antiviral treatment with oseltamivir or zanamivir is recommended as early as possible for any patient with confirmed or suspected influenza who: is hospitalized; has severe, complicated, or progressive illness; or is at higher risk for influenza complications.
- Do not wait for laboratory confirmation of influenza when deciding whether to begin antiviral treatment.
- Antiviral treatment is most effective when administered 48 hours within illness onset, but some studies suggest that antivirals may be beneficial when taken up to 4-5 days after illness onset.
- Antiviral chemoprophylaxis should be used for prevention of influenza when indicated for institutional influenza outbreaks, and may be considered for those who have contraindications to influenza vaccination.
- For patients who do not respond to antiviral treatment, antiviral susceptibility laboratory testing should be considered.
- Antibiotics are not effective against influenza. See CDC’s Get Smart website for more information on the appropriate use of antibiotics in the healthcare setting.
- CDC Health Advisory Regarding the Potential for Circulation of Drifted Influenza A (H3N2) Viruses (December 3, 2014)
- CDC Health Update Regarding Treatment of Patients with Influenza with Antiviral Medications (January 9, 2015)
- CDC Health Advisory Regarding Rapid Treatment of Patients with Influenza with Antiviral Medications (February 1, 2016)
Role of testing in making treatment decisions
- To make treatment decisions, diagnostic testing is not necessary for all patients with signs and symptoms of influenza. Once influenza activity has been documented in the community or geographic area, a clinical diagnosis of influenza can be made for outpatients with signs and symptoms consistent with suspected influenza, especially during periods of peak influenza activity in the community.
- If influenza is suspected clinically and antiviral treatment is indicated, treatment should not be delayed while waiting for the results of flu testing.
Rapid influenza diagnostic tests
- Rapid influenza diagnostic tests (RIDTs) can be useful to identify influenza virus infection. These tests produce very quick results, but the results need to be interpreted with caution. Sensitivity of these tests generally ranges from 40-70%. False positive results are not as common (specificity ranges from 85-100%).
- A negative RIDT result does not exclude a diagnosis of influenza in a patient with suspected influenza.
- To minimize false rapid influenza diagnostic test results:
- Collect specimens as early in the illness as possible (ideally within 48-72 hours of illness onset)
- Follow manufacturer’s instructions, including acceptable specimens and handling
- Follow-up negative results with confirmatory tests (RT-PCR or viral culture) if a laboratory-confirmed influenza diagnosis is desired
- Strategies for Improving Rapid Influenza Testing in Ambulatory Settings – four free 30-minute online courses developed by The Joint Commission
Other types of testing
- Other testing (immunofluorescence, RT-PCR, viral culture) is more accurate, but can take longer. Molecular tests are helpful in the identification of novel influenza viruses.
- Patients suspected of having novel influenza infection require specialized testing that must be coordinated through your local health department. Relevant illness and severity criteria as well as exposure history criteria (such as recent travel to areas where novel human influenza infections have occurred or recent contact with swine) must be met before public health testing occurs. To learn more about specific testing criteria and specimen collection procedures, consult the VDH Novel, Variant, and Pandemic Influenza page. Be sure to report any unusual influenza cases to your local health department.
- Periodically throughout the influenza season, positive flu specimens are forwarded by public health laboratories to CDC for testing for resistance to oseltamivir and zanamivir.
Additional testing information
- For more information on clinical description and laboratory diagnosis of influenza including a testing algorithm, click here.
- To view an instructional video that demonstrates how to collect a nasopharyngeal (NP) swab, click here.
Sentinel influenza surveillance testing
- Some clinicians participate in a sentinel surveillance system with VDH by collecting samples for confirmatory influenza testing at the state public health laboratory. These specimens help characterize the strains that are circulating in the community. For information on sentinel surveillance testing for public health, click here.
- Vaccination recommendations and protocols
- Influenza vaccination of healthcare personnel
- To report an adverse event associated with influenza vaccination, click here (Vaccine Adverse Event Reporting System)
- Fact sheets
- CDC Get Smart campaign print materials
- CDC seasonal influenza resources
Resources for Long-Term Care Facilities (Including Assisted Living Facilities)
- CDC Toolkit: Increasing Influenza Vaccination among Healthcare Personnel in Long-Term Care Settings
- Interim Guidance for Outbreak Management in Long-Term Care Facilities (CDC)
- Fact sheets
- Guidelines for the Prevention and Control of Influenza in Non-Healthcare Group Settings (Aug 2015) (VDH) – applicable to assisted living facilities
- Guidelines for the Prevention and Control of Influenza in Nursing Homes and Long-Term Care Facilities (Aug 2015) (VDH)
Surveillance and Reporting
- For more information about sentinel surveillance, current influenza activity levels, and healthcare facility reporting requirements in Virginia, click here.
- National flu activity and surveillance (CDC)
- Healthcare personnel influenza vaccination reporting requirements for healthcare facilities