Home tests are a valuable tool to support the management of influenza and other respiratory infections. The tests facilitate earlier diagnoses and reduce the time from the onset of symptoms to patients seeking appropriate care. The researchers determined that the sensitivity and specificity of the self-test were comparable with those of influenza rapid diagnostic tests used in clinical settings. False-negative results were more common when the self-test was administered after 72 hours of the appearance of symptoms but were not related to inadequate swab collection or severity of illness.
According to the U.S. Centers for Disease Control and Prevention, the most recent influenza season in the United States, between October 2019 and April 2020, led to 38 million illnesses, 18 million medical visits, 400,000 hospitalizations, and 22,000 deaths. In comparison, the Centers for Disease Control and Prevention reports that between Sept 2020 and May 2021 in the United States, 1,675 of 810,000 respiratory specimens tested by U.S. clinical laboratories were positive for an influenza virus.
Influenza (the flu) is a viral respiratory illness that affects millions of people each year. Symptoms can include fever, cough, stuffy or runny nose, sore throat, headache, chills, and fatigue. A flu test is not always needed to diagnose the flu. However, in some cases, your health care provider may need to confirm if you have the flu, so they may recommend testing.
How to test for flu
There are a number of tests used to diagnose the flu. The most common are rapid influenza diagnostic tests (RIDTs), and they may be performed in a health care provider’s office. RIDTs work by detecting antigens (parts of the virus) that stimulate an immune response. Your doctor will rub a swab along the back of your throat or up your nose. They’ll seal it in a packet and run a quick test on it themselves, or send it out to a lab.
A rapid molecular assay is another flu test that works by detecting genetic material from the virus. In addition to rapid tests, there are several more accurate and sensitive flu tests that must be performed in specialized laboratories, such as those found in hospitals or state public health laboratories. A flu test typically involves a health care provider collecting a sample from the inside of your nose or back of your throat using a sterile swab. The swab is then tested for flu.
How accurate is the flu test?
The accuracy of the flu test depends on which kind of test is performed and the type of influenza that’s going around. While RIDTs are the most common flu tests, they are not as accurate as other types of flu tests, but they seem to be better at detecting the flu in children than adults. In general, if you receive a positive rapid test during a flu outbreak, it likely means you’re infected with the flu. Note that false negative (meaning the test is negative but you really have the flu) and false positive (meaning the test is positive but you actually do not have the flu) test results can occur.
