Test guide
Flu (Influenza) Test
Flu is short for influenza. It is a respiratory infection caused by viruses . Respiratory infections may affect your nose, throat, and/or lungs. Most flu tests check a sample of fluid from your nose or throat to find out if you're infected with a flu virus.
What it is for
If you have symptoms of a respiratory infection, a test for common seasonal flu may be used to help find out if the influenza A or B virus is causing your illness. Knowing whether you have the flu is especially important if you have a high risk of becoming seriously ill from the flu. The test results can help your provider decide if medicine could help treat your illness and which one might help you. Public health officials may also use flu tests to monitor flu and COVID-19 outbreaks in the community. Source: MedlinePlus, National Library of Medicine. Medical test information is public domain. Source identity and definition checked automatically on 2026-10-18. No individual clinical interpretation or human reviewer is asserted.
Limitations
Reference intervals and interpretation depend on the laboratory, specimen, method and clinical context. This source definition is educational information; it does not establish a diagnosis, product approval or suitability for an individual.
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