Rapid Flu Test
Reasons to Get One, What to Expect, Associated Risks & More

4 Reasons You Would Need a Rapid Flu Test

1. Receiving a Proper Diagnosis

Symptoms of the flu are similar to those for many other health and medical conditions. A rapid flu test allows you and your doctor to determine whether you’re suffering from the flu or from another condition that requires a different treatment. Bacterial infections and viral infections share many of the same symptoms, but drugs like antibiotics do not treat viral infections like the flu and can have adverse effects.[1] A rapid flu test rules out other conditions so you can receive a proper diagnosis and receive safe treatment using the right medications.

Previously, it was thought that the influenza B virus produced milder symptoms than the influenza A virus, and the rapid flu test identified which virus caused symptoms. However, new evidence shows that the symptoms produced by both viruses are equal in severity and can be effectively treated using the same methods.[2]

2. Shortening Illness

Influenza symptoms usually set in within one to four days of being infected and can last for up to two weeks.[3] A rapid flu test helps detect the virus early so you can immediately receive antiviral medications that reduce symptoms. Visiting the doctor the moment you begin experiencing symptoms is critical, as detection of the flu within 48 hours can help shorten your illness by at least one day.[4] Waiting for more than two days to visit the doctor after flu symptoms begin may prevent antiviral medications from shortening your illness.

Common flu symptoms include sore throat, headache, cough, fever, chills, fatigue, congestion, and muscle aches.[5] Receiving a rapid flu test within two days of experiencing these symptoms can help you shorten your illness if you have influenza.

3. Preventing Flu Complications

In some cases, influenza can lead to more serious complications and medical conditions, such as pneumonia, organ failure, encephalitis, and myocarditis.[5] Flu viruses that infect the respiratory tract can cause sepsis, a life-threatening condition in which toxins and bacteria attack healthy tissues and organs to cause symptoms that include rapid heart rate, fever, extreme pain, and even death.[6] Flu can also worsen existing medical conditions, such as asthma and chronic heart disease.

A rapid flu test can help you prevent complications from the flu by offering a quick and proper diagnosis. People at highest risk for experiencing flu complications include children under the age of five, pregnant women, people aged 65 and older, and residents of nursing homes. Flu complications could also be deadly for those who suffer from blood, kidney, liver, and endocrine disorders, or from weakened immune systems caused by conditions such as HIV, AIDS, and cancer.[7]

4. Preventing Flu Pandemic

A flu pandemic happens when a new flu virus for which there is no immunity spreads between people and communities, causing widespread illness. A flu pandemic can overwhelm hospitals, lead to limited access to flu vaccines, and even put healthy people at risk for illness and related complications.[8] A rapid flu test can detect the type of influenza virus causing your infection and help you, your family members, and local community stay safe and prevent a flu pandemic.

Understanding a Rapid Flu Test

The rapid flu test helps your doctor determine whether your symptoms are caused by the influenza virus. A flu test involves taking fluid samples from your nose or throat and analyzing them in a lab. Test results are usually available within 15 to 20 minutes.[9] If you test positive for the flu, you can be treated by your doctor immediately to reduce flu symptoms. Evidence suggests that the rapid flu test may not be as accurate as other flu tests; some people still have the flu despite negative test results.

The purpose of a rapid flu test is to determine whether you have the flu so you can take advantage of early treatment. Early treatment can prevent symptoms from peaking in severity and from contributing to more serious health problems and medical conditions.

What to Expect With a Rapid Flu Test

The rapid flu test itself takes just a few minutes and can be performed using a cotton swab or nasal spray.[10] With a swab test, your doctor gently uses a long swab to collect a fluid sample from your nose or back of your throat. With the nasal spray method, your doctor injects saline solution into your nose and uses gentle suction to collect the sample. The sample is then analyzed in a lab, and your doctor typically receives results within 20 minutes.

If the rapid flu test comes back positive for influenza, your doctor can begin treatment to reduce your symptoms and prevent them from worsening. Doctors often prescribe medications that effectively relieve flu symptoms.

Risks of a Rapid Flu Test

There are no risks associated with undergoing a rapid flu test, but you could experience gagging or discomfort when the doctor uses a swab to collect fluid from your throat or nasal cavity. Some rapid flu tests require the doctor to suck a fluid sample from the nose, and this can also cause some discomfort.

Questions to Ask Your Doctor About a Rapid Flu Test

  • How should I prepare for a rapid flu test?
  • Will the rapid flu test cause me to feel any pain or discomfort?
  • Can I be prescribed medications right away to treat the flu if my test is positive?
  • Can I take a second rapid flu test to confirm the diagnosis if my first test comes back negative?
  • Do I need to have flulike symptoms in order to receive a rapid flu test?

Rapid Flu Test May Also Be Known as

  • Rapid influenza diagnostic test
  • RIDT
  • Influenza antigen test
  • Flu PCR


  1. Centers for Disease Control and Prevention. Be Antibiotics Aware: Smart Use, Best Care. https://www.cdc.gov/features/antibioticuse/index.html
  2. Centers for Disease Control and Prevention. New CDC Study Compares Severity of Illness Caused by Flu A and B Viruses. https://www.cdc.gov/flu/news/flu-study-viruses.htm
  3. University of Rochester Medical Center. Rapid Influenza Antigen (Nasal or Throat Swab). https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=rapid_influenza_antigen
  4. Centers for Disease Control and Prevention. Influenza Antiviral Medications: Summary for Clinicians. https://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm
  5. Centers for Disease Control and Prevention. Flu Symptoms & Complications. https://www.cdc.gov/flu/consumer/symptoms.htm
  6. Centers for Disease Control and Prevention. Sepsis: What are the signs and symptoms? https://www.cdc.gov/sepsis/signs-symptoms.html
  7. Centers for Disease Control and Prevention. People at High Risk of Developing Flu–Related Complications. https://www.cdc.gov/flu/about/disease/high_risk.htm
  8. Centers for Disease Control and Prevention. How Is Pandemic Flu Different from Seasonal Flu? https://www.cdc.gov/flu/pandemic-resources/basics/about.html
  9. Centers for Disease Control and Prevention. Diagnosing Flu. https://www.cdc.gov/flu/about/qa/testing.htm
  10. National Library of Medicine. Flu (Influenza) Test. https://medlineplus.gov/labtests/fluinfluenzatest.html

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