Exams and Tests

In most cases, diagnosis of the flu is determined by the symptoms, especially when these occur during the peak flu season. Sometimes, the doctor may need to perform special tests to be sure the influenza virus is responsible for the symptoms.

A sample is taken from the back of the throat or nose. To take a sample, the doctor uses a cotton-tipped wooden stick and simply rubs the cotton tip at the back of the throat or inside the nose. The sample is sealed in a packet and sent to the lab for testing. Some offices may use a rapid test that can be performed in the office with the result available in 30 minutes. Some rapid tests detect only influenza A virus, while others can detect both influenza A and influenza B. Some cases of the flu may be missed by the rapid tests.