Criteria for novel H1N1 influenza testing at the MA State Laboratory remain unchanged
September 29, 2009
Testing for pandemic H1N1 2009 influenza is complicated by poor sensitivity of rapid tests for influenza A and delays associated with more definitive testing. As such, CDC and DPH recommend that individuals who are either hospitalized with severe respiratory illness OR who
are at high risk for complications from influenza be treated for influenza empirically, as soon as possible after symptom onset. Decisions regarding treatment, selection of antiviral agents, and isolation should be based on clinical factors and should not be contingent on laboratory confirmation of novel H1N1 influenza.
HSLI will continue to perform novel H1N1 influenza testing ONLY where confirmatory results will significantly impact clinical management of a patient, or where there is a clear public health benefit. All testing must be approved in advance by a DPH epidemiologist. HSLI will also continue to test a representative subset of specimens collected at influenza sentinel sites for disease surveillance purposes.
Rapid influenza tests can have an unacceptably low sensitivity when used for diagnosis of novel H1N1 influenza, and should not be used to rule out the presence of the virus. Other commercially-available influenza tests, such as DFA and PCR, may be useful in the diagnosis of H1N1; however, clinicians should interpret these test results with an understanding of the test’s sensitivity and specificity, and with consideration of the circulating influenza strain types.
Our latest recommendations pertaining to H1N1 are on the DPH website at www.mass.gov/dph/flu. Information from CDC can be found at www.cdc.gov/h1n1flu. Clinicians and laboratories can contact a DPH epidemiologist at 617-983-6800 (available 24/7) with any questions regarding test, treatment, or control measures
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