A number of flu tests are available to detect influenza viruses in respiratory specimens. The most common are called “rapid influenza diagnostic tests (RIDTs).” RIDTs work by detecting the parts of the virus (antigens) that stimulate an immune response. These tests can provide results within approximately 10-15 minutes but are not as accurate as other flu tests. Therefore, you could still have flu, even though your rapid test result is negative. Other flu tests are called “rapid molecular assays” that detect genetic material of the virus. Rapid molecular assays produce results in 15-20 minutes and are more accurate than RIDTs. In addition, there are several more accurate and sensitive flu tests available that must be performed in specialized laboratories, such as those found in hospitals or state public health laboratories. All of these tests require that a health care provider swipe the inside of your nose or the back of your throat with a swab and then send the swab for testing. Results may take one to several hours.