Rapid detection flu test may return inaccurate results

HOUSTON, Texas (KTRK) -- There's no running from it.

Flu season is in full swing, but now medical experts say how you get tested for the flu may also be a problem.

The most commonly used test, called a rapid detection test, is a simple nose swab that can give results within 15 minutes.

It is the fastest way to determine if you have the flu, but Dr. Michael Chang with Children's Memorial Hermann Hospital and UT Health warns those quick results are often wrong.

"Negative testing from the rapid test is actually a well-known problem and there's a lot of things that go into that," Dr. Chang said. "Part of it is just the nature of the test itself. Other things to think about -- that you may not consider -- is how the specimen was obtained. Did they actually do the swab correctly? Did they put it in enough? Did they turn it enough? Did they get a good specimen? Was it performed correctly in the lab?"

The test is so unreliable that Memorial Hermann Hospital has decided to stop using it, instead deferring to a molecular test.

"The molecular testing does require some additional equipment and some additional expertise, and so not everyone is going to have that. I think most places that you go like primary care and urgent care will be using the rapid detection kits," said Dr. Chang.