How fast and reliable is the rapid flu test?

15 minutes: I'm sure it depends somewhat on the brand of the test, but the one we use in our office uses a nasal swab specimen, takes 15 minutes to run, and has a specificity of 95%. Because it is important to treat patients with the flu within 48 hours of onset of symptoms, having a rapid test is very helpful. Better yet, however, is to get a flu vaccine and reduce the risk of getting sick!

Clinical judgement: Depending on a number of factors, in an area where lots of people are catching the flu, the sensitivity rapid flu testing can drop below 50%. Therefore, it important that a skilled clinician using their clinical judgement if a pt has obvious symptoms of the flu and the test result is negative- it may likely be a false negative.