How is the flu diagnosed?

The flu, or Influenza, is typically diagnosed based on symptoms and a physical examination. Your doctor may also use one or more of the following diagnostic tools to confirm the diagnosis:

1. Rapid Influenza Diagnostic Test (RIDT): This is a simple and quick test that can detect the presence of flu viruses in your nose or throat. The results are usually available within 15 minutes.
2. Viral Culture: This test involves collecting a sample of your respiratory secretions (such as mucus) and sending it to a laboratory to grow the virus. This test is more accurate than the RIDT, but it takes longer to get the results (usually a few days).
3. Blood Test: A blood test can measure the levels of flu-specific antibodies in your blood, which can confirm the presence of the flu virus.

In some cases, your doctor may also use chest X-rays or other imaging tests to rule out other causes of your symptoms.

It’s important to see a doctor as soon as possible if you think you have the flu, as early treatment can help reduce the severity and duration of the illness. Antiviral medications are most effective when started within the first two days of symptoms.