Collecting a sample for a flu test can take less than 1 minute. The wait time for results may range from 15 minutes to 4 hours, depending on the type of test.

hand wearing blue medical glove holding a cotton swabShare on Pinterest
Blake Callahan/Getty Images

A positive flu test result may help you get effective treatments, such as antiviral medications that can shorten the flu’s duration.

Multiple types of flu tests are available, and many of them can provide rapid results.

If you’re experiencing symptoms such as a fever, fatigue, body aches, and a sore throat, here’s a rundown of how quickly you can expect to find out whether those symptoms mean you have the flu.

Getting a flu test is not usually a time-consuming experience. A healthcare professional might use one of the following methods to collect a sample:

  • Deep nasal swab: A healthcare professional will insert a swab about 1 inch into your nostril. This type of swab does not need to be inserted as deeply as a nasopharyngeal swab (see below).
  • Nasopharyngeal or nasal aspirate: This less common method involves using a suction catheter to collect a sample of mucus. When the suction catheter is inserted very far into the back of your throat, doctors call this a nasopharyngeal aspirate sample.
  • Nasopharyngeal swab: For this test, a healthcare professional will ask you to tilt your head back and will then swab both nostrils. They will insert the swab until there’s an equal distance between your nostril and your outer ear opening.
  • Throat or nasal swab: This testing method involves using both a nasal swab and a throat swab that reaches back into the tonsil area of your throat.

Sample collection for any of these testing methods usually takes no more than 1 minute, but the wait for your results will be longer.

Thanks to innovations in flu testing, you may get results in as little as 10 to 15 minutes. Doctors refer to these as rapid tests. According to the Centers for Disease Control and Prevention (CDC), rapid tests may be more accurate for detecting the flu in children than in adults.

With these and other flu tests, it is possible to get a false-negative result, which means that a test result might not show that you have the flu even when you do. In addition to the test result, a doctor should consider your symptoms and whether you’ve spent time around anyone who has recently received a flu diagnosis.

Several types of tests are available for the influenza virus. Some check for the presence of the flu virus, while others test your body’s response to the virus. Test types and their result times are as follows:

Immunofluorescence

This testing type typically involves using a special microscope to identify flu antigens (antibodies to the flu). While a rapid test can show a result in about 15 minutes, most tests take 2 to 4 hours to provide results.

Rapid influenza diagnostic tests (RIDTs)

RIDTs check for the presence of viral antigens, which your body produces in response to the flu virus.

These tests are not as sensitive (accurate) for the flu as other test types and can often produce a false-negative result. Also, a positive result may not mean you have an active form of the flu. Results typically take about 15 minutes.

Rapid molecular assay

This is a rapid test designed to identify influenza nucleic acids (genetic material). According to the CDC, rapid molecular assay tests are highly sensitive and specific for the flu. These tests can usually provide results in 15 to 30 minutes.

Doctors refer to this type of test as point-of-care testing, which means it can be performed in the doctor’s office and does not require sending a sample to a laboratory.

Reverse transcription-polymerase chain reaction (RT-PCR)

RT-PCR tests can detect flu genetic material to highly accurate levels. They might also help determine whether you have influenza type A or type B. Results for these tests can take anywhere from 45 minutes to a few hours.

If you visit a doctor because you think you might have the flu, you can ask them which type of test they use.

Generally, if your flu test result is positive, you have the flu.

If your flu test result is negative, you might not have the flu. But you might get a false-negative result if the test you received does not recognize the flu strain you have or if the person who performed your test did not collect enough material to accurately detect the flu.

Rapid antigen tests are 50% to 70% accurate, although the Food and Drug Administration (FDA) has required more recent tests to make changes to improve their results.

Rapid molecular tests are anywhere from 66% to 100% accurate, but the results and accuracy depend on which test type you use.

Tests are most likely to be accurate when a sample is tested within 3 to 4 days of the start of your flu symptoms.

Less is known about flu tests’ abilities to detect the flu in people who don’t have symptoms. This is because most people seek out tests when they feel unwell.

Flu tests are available at most doctors’ offices, urgent care centers, and hospitals.

Rapid flu tests usually cost less than laboratory-based tests.

You might want to contact a facility to make sure flu tests are available, especially during flu season, which is usually in the late fall and winter. Facilities might run out of tests on some busy days.

Alternatively, you can buy a rapid test at a pharmacy or online and take the test at home.

Flu tests can provide rapid results that are becoming increasingly accurate. Doctors may select a type of test based on availability and accuracy.

You’re more likely to get a false-negative result than a false-positive one. For this reason, a doctor may treat your symptoms as if you have the flu, even if your test is negative.