Laboratory Collection and Testing Information about the H1N1 Virus
Physician Questions about H1N1 Testing
Online H1N1 Resources for Clinicians
Physician Questions
How do I collect a sample from a patient I want tested for swine flu?
A good specimen to collect for the 2009 H1N1 (swine flu), or any influenza, is a nasal pharyngeal swab, but it must be collected correctly to obtain enough cells for the test to work, refer to the Viral Pertussis Collection instructions. A wash or aspirate is also acceptable for direct testing and/or culture. Remember to submit all swabs in Viral Transport Media. We currently supply either M4 or M6 media.
NOTE: Legacy will perform culture or direct fluorescent antibody stains on bronchaveoloar lavage specimens and tracheal aspirates. The FDA has not approved these specimens for molecular testing. Molecular testing will only be performed on nasal specimens.
What test should I order?
Currently, you can order an Influenza Rapid Detection (Rapid Flu) by DFA or you can order an Influenza Culture (C Flu). The turn around time for the Rapid Flu is 24 hours. The turn around time for the Influenza Culture is 72 hours. The sensitivity for finding influenza by the Rapid Flu test is 75-85%, while the sensitivity for culture is 85-95%.
Can I get the test done STAT?
This test requires a skilled virologist to set up and read, so the tests are performed from 0700 to 1530 hours daily. Specimens coming in after 1400 hours may be held over to the next morning for testing.
Will this test tell me if my patient has swine flu?
The Rapid Flu test and the Influenza Culture will only tell you if the test is positive for Influenza A, Influenza B or neither. It cannot subtype the organism as to whether it is the seasonal flu or the swine flu. At this time, any positive Influenza A from an inpatient is sent to the Oregon State Public Health Lab for subtyping for the 2009 H1N1 (swine flu). The state will not accept specimens or isolates from outpatients at this time. Their subtyping is for epidemiological purposes only, and not for diagnostic purposes. Focus Labs in California is the only FDA approved lab that can perform molecular subtyping for the 2009 H1N1, outside of the public health labs. The cost for getting a sample subtyped at Focus Labs is around $328. As there is no medical reason to subtype, insurance may not pay for that cost, so patients should be made aware of this.
If I can't get the sample subtyped for H1N1, how will I know if my patient has swine flu or not?
Currently, the only influenza circulating in our state is the 2009 H1N1 (swine flu) strain. So if a sample is positive for Influenza A, you can assume it is the 2009 H1N1. When the seasonal influenza season begins and we get other flu strains in our community, additional testing will be available to subtype for the 2009 H1N1.
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Online Resources
Centers for Disease Control
Oregon State
Washington State
Other H1N1 websites
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