Skip to content
My WebMD Sign In, Sign Up

Cold, Flu, & Cough Health Center

Select An Article
Font Size

Flu Test: Detecting Flu Viruses

In most cases, a doctor can diagnosis the flu based on symptoms, especially when these symptoms occur during the peak flu season. But sometimes your doctor may want to perform an influenza rapid diagnostic test to be sure the influenza virus is responsible for your symptoms and not another health problem.

Why Is a Flu Test Helpful?

When your doctor distinguishes the flu virus from other viral infections, antiviral drugs can be prescribed early in the illness when they are most effective. If the flu is diagnosed early (within 48 hours of showing flu symptoms), the antiviral drugs may alleviate the severity of the flu symptoms. After 48 hours, these drugs may not have any benefit in reducing flu symptoms. 

In addition, a flu test may help reduce the incidence of antibiotics being inappropriately used for the flu virus.

 

How Does a Flu Test Work?

First, your doctor will take a sample from the back of your nose or throat. To collect this sample, the doctor will swab your nasal passage or throat. The doctor will then seal the sample in a packet and  run a rapid test on site or send it to a lab for testing.

How Long Does It Take to Get Flu Test Results?

The rapid diagnostic flu tests usually provide results within 15 minutes.

What Does the Flu Test Detect?

Some rapid flu tests can help distinguish between influenza A and B virus. As with any tests, the accuracy of the test depends on the quality of the manufacturer’s test, sample collection method, and how much viral sample a person is shedding at the time of testing.  

WebMD Medical Reference

Reviewed by Kimball Johnson, MD on June 11, 2012
Next Article:

Today on WebMD

neti pot
Slideshow
Chicken soup
Slideshow
 
Natural Cold Flu Remedies Slideshow
Slideshow
Syringes and graph illustration
TOOL
 
Natural Cold Flu Remedies Slideshow
Slideshow
blowing nose
Video
 
Allergy And Sinus Symptom Evaluator
Health Check
Boy holding ear
Article
 
woman receiving vaccine shot
Article
Bacterial or Viral Infection
Video
 
How To Calm Your Cough
Quiz
Sore Throat
Slideshow
 

WebMD Special Sections