Influenza (the flu) is a contagious respiratory (breathing) illness caused by the influenza virus. A timely and accurate diagnosis is important for effective treatment and stopping the spread of the virus.
At Banner Health, we want you to get the best care so that you can return to good health as fast and safely as possible. Part of that care is learning how the flu is diagnosed.
Several health care providers can diagnose and treat the flu, including:
If you think you have flu symptoms, taking the right steps for proper medical care is essential. You can visit your health care provider in person or virtually (online) using a telehealth appointment.
Virtual visits allow you to get the care you need from the comfort of your home. However, this option may not be best if you need more hands-on care. This includes people at high risk for complications, such as children under 5 years old, adults over 65, pregnant people and people with chronic medical conditions and/or weakened immune systems.
Your provider may use the following methods to diagnose the flu:
Your provider may recommend a flu test if you show symptoms such as a high fever, sore throat, coughing or body aches. They may also order a flu test if you are at greater risk for complications.
Getting a quick flu diagnosis can help you with treatment, including the use of antiviral medications. Ideally, testing should occur within the first 48 hours (about two days) of experiencing symptoms.
You may also need to take a flu test so that public health officials can determine if there is an outbreak of the flu in your community.
There are several tests used to diagnose the flu. All involve a quick swab of your nose or throat to get a viral sample. The most common are rapid influenza diagnostic tests (RIDTs). Other tests include rapid molecular assays and specialty flu tests, including the reverse transcription-polymerase chain reaction (RT-PCR) test.
At-home rapid flu screening kits and combination test kits that identify flu, RSV (respiratory syncytial virus) and COVID-19 are also now available. These tests involve collecting your own sample using a nasal swab. Results are available in about 30 minutes—no lab required.
These kits can save you time and an office visit, but you must carefully follow test directions to get accurate results.
The accuracy of the flu test depends on the type of test and the flu strain that is going around.
RIDTs are the most common flu test, but molecular assays are more sensitive and accurate. RIDTs detect the presence of the flu virus 50-80% of the time, so false negative results are possible. Molecular assays, however, are 90-95% accurate.
Your provider will provide treatment options if you test positive for the flu. This may include rest and self-care, taking antiviral medication and getting a flu shot once you recover (if you haven’t had one this season).
The results from your test will likely be anonymously shared with your state’s Department of Health to help the Centers for Disease Control and Prevention (CDC) track any flu outbreaks.
Getting diagnosed with the flu is important for your well-being and the well-being of those around you. Early diagnosis allows for quick treatment, lessens any complications and helps limit the spread of the virus.
Remember, prevention is always better than getting sick. Getting a flu shot every year and regular hand washing is your best defense against the flu.