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U.S. Department of Health and Human Services

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Fact Sheet For Healthcare Providers: Interpreting CDC rRT-PCR Swine Influenza Detection Panel Test Results

The information previously contained on these webpages were authorized under the 2009 H1N1 Influenza Emergency Use Authorizations (EUAs). As of June 23, 2010, the EUAs have been terminated and this information is no longer current.

December 18, 2009

A public health emergency has been declared by the Secretary of Health and Human Services because of the outbreak of the 2009 H1N1 influenza virus, (previously referred to as swine influenza (H1N1) virus). This fact sheet will refer to the virus as 2009 H1N1 influenza virus. The Food and Drug Administration (FDA) has authorized the emergency use of the Swine Influenza Virus Real-time RT-PCR Detection Panel (rRT-PCR Swine Flu Panel) to test for the presence of the 2009 H1N1 influenza virus in clinical specimens. These specimens should be collected via upper respiratory specimens such as nasopharyngeal swabs, nasal swabs, throat swabs, nasal washes, nasal aspirates or lower respiratory specimens such as bronchoalveolar lavage (BAL), bronchial aspirate (BA); bronchial wash (BW); endotracheal aspirate (EA); endotracheal wash (EW); tracheal aspirate (TA), and , lung tissue from patients with signs and symptoms of respiratory infection , and viral culture. This authorization will terminate on April 26, 2010, unless (1) it is revoked sooner, (2) the declaration of emergency is terminated sooner, or (3) the declaration of emergency is renewed for a longer term. The information in this Fact Sheet is the minimum necessary to inform you of the significant known and potential risks and benefits of the emergency use of the rRT-PCR Swine Flu Panel.

 At this time, there are no  FDA-approved/cleared tests that identify the existence of the 2009 H1N1 influenza virus in clinical specimens. Previously, the FDA granted Emergency Use Authorization for other tests intended to diagnose 2009 H1N1 influenza virus, see http://www.fda.gov/MedicalDevices/Safety/EmergencySituations/ucm161496.htm for more information. To augment existing testing capacity and testing specimen types, FDA has authorized the emergency use of the CDC Swine Influenza Virus Real-time RT-PCR Detection Panel on the Applied Biosystems 7500 Fast Dx and on LightCycler® 2.0 instruments to detect 2009 H1N1 influenza virus infections. Current information on 2009 H1N1 influenza virus, including case definitions and infection control guidelines, is available at http://www.cdc.gov/h1n1flu/.Exit Disclaimer All information and guidelines, including those on testing for 2009 H1N1 influenza A virus, may change as we continue to learn more about this disease. Please check CDC’s 2009 H1N1 influenza virus website regularly for the most current information.

The rRT-PCR Swine Flu Panel test should be ordered only to diagnose 2009 H1N1 influenza virus infection . This test is authorized for use with upper respiratory tract clinical specimens such as nasopharyngeal swabs (NPS), nasal swabs, throat swabs (TS), dual NPS/TS swab specimens, nasal aspirates and nasal washes, and lower respiratory tract specimens such as endotracheal aspirate, broncheoalveolar lavage fluid, lung tissue, and viral culture. Specimen collection should be conducted per the clinical protocol and according to the manufacturer’s instructions for the specimen collection device and sent to a qualified laboratory for analysis . For additional information on specimen collection, please refer to: http://www.cdc.gov/h1n1flu/specimencollection.htm.Exit Disclaimer The risks of collecting these specimens (nose or throat discomfort, cough or bloody nose or brief respiratory distress) should be shared with the patient.

 What does it mean if the specimen tests positive for 2009 H1N1 influenzavirus?

A positive test result for 2009 H1N1 influenza virus using the rRT-PCR Swine Flu Panel indicates that the patient is infected with 2009 H1N1 influenza virus. The test does not indicate the stage of infection. Laboratory test results should always be considered in the context of clinical observations and epidemiologic data in making a final diagnosis. For guidelines on managing patients please refer to “Interim Guidance on Infection Control Measures for 2009 H1N1 Influenza in Healthcare Setting, Including Protection of Healthcare Personnel” http://www.cdc.gov/h1n1flu/guidelines_infection_control.htmExit Disclaimer and “Updated Interim Recommendations for the Use of Antiviral Medications in the Treatment and Prevention of Influenza for the 2009-20010 Season” at  http://www.cdc.gov/h1n1flu/recommendations.htm.Exit Disclaimer

The rRT-PCR Swine Flu Panel test has been designed to minimize the likelihood of false positive test results. However, in the event of a false positive result, risks to patients could include any or all of the following: recommendation to limit contact with uninfected persons (including at home or at the workplace), a prescription of antiviral medication or other therapy, the impaired ability to detect and receive appropriate medical care for the true infection causing the flu like symptoms, or other unintended adverse effects.

What does it mean if the specimen tests negative for the 2009 H1N1 influenza virus?

Negative results do not preclude influenza virus infection and should not be used as the sole basis for treatment or other patient management decisions. The clinical features of the illness and the type and risk of exposure are the keys to making patient management and isolation decisions. A negative test result from the rRT-PCR Swine Flu Panel test should not be interpreted as demonstrating that the patient does not have 2009 H1N1 influenza virus infection, if other aspects of the patient’s clinical presentation or recent epidemiologic exposures indicate 2009 H1N1 influenza virus infection is likely, and diagnostic tests for other causes of acute respiratory illness are negative.

Contact Information:

Please note that for any questions or concerns (including interpretation of test results) about the product, please contact the laboratory performing the diagnostic test. The laboratory has been trained and qualified by CDC personnel.

Test Manufacturer

CDC Influenza Division
1600 Clifton Road, MS-G03
Atlanta GA 30333
Contact phone 404-6390954

Contact email flusupport@cdc.gov

* For additional information please visit http://www.cdc.gov/h1n1flu/eua/.Exit Disclaimer This web site will also contain any significant new findings observed during the course of the emergency use of rRT-PCR Swine Flu Panel.