Influenza (flu)

Diagnosis

To diagnose the flu, also called influenza, your healthcare professional does a physical exam, looks for symptoms of flu and may order a test that detects flu viruses. During flu season, you may not need a flu test.

But a test for flu may be suggested to help guide your care or to know if you could spread the virus to others. A flu test may be done by a pharmacy, your healthcare professional's office or in the hospital.

For people age 2 and older, a test you can take at home may be available. If you do use an at-home test, let your healthcare professional know the results. You may need to confirm the results, positive or negative, with a test from your healthcare team.

Types of flu tests you may have include:

• Molecular tests. These tests look for genetic material from the flu virus. Polymerase chain reaction (PCR) tests are molecular tests. Another name for this type of test is nucleic acid amplification test (NAAT).
• Antigen tests. These tests look for viral proteins called antigens. Rapid influenza diagnostic tests are one example of antigen tests.

It's possible to have a test to diagnose both flu and other respiratory illness, such as COVID-19, which stands for coronavirus disease 2019. You may have both COVID-19 and influenza at the same time.

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Treatment

If you have a severe infection or are at high risk of complications from a flu infection, your healthcare professional may prescribe an antiviral medicine to treat the flu. These medicines can include oseltamivir (Tamiflu), baloxavir (Xofluza) and zanamivir (Relenza).

You take oseltamivir and baloxavir by mouth. You inhale zanamivir using a device similar to an asthma inhaler. Zanamivir shouldn't be used by anyone with certain chronic respiratory conditions, such as asthma and lung disease.

People who are in the hospital may be prescribed peramivir (Rapivab), which is given in a vein.

These medicines may shorten your illness by a day or so.

Antiviral medicine may cause side effects. These may include breathing symptoms, nausea, vomiting or loose stools called diarrhea. Check the prescription information for details.

Clinical trials

Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this condition.

Lifestyle and home remedies

If you have the flu, these measures may help ease your symptoms:

• Drink plenty of liquids. Choose water, juice and warm soups to help keep fluids in your body.
• Rest. Get more sleep to help your immune system fight infection. You may need to change your activity level, depending on your symptoms.
• Consider pain relievers. Use acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin IB, others) for fever, headache or achiness associated with influenza. Children and teens recovering from flu-like symptoms should never take aspirin because of the risk of Reye's syndrome, a rare but potentially fatal condition.

Stay home until you feel better and have had no fever for a full 24 hours, and you haven't taken medicine for fever during that time. If your fever returns or you start to feel worse, stay apart from others until your symptoms improve and you are fever-free without medicine for 24 hours. Doing so will lower your chance of infecting others.