Rapid EIA (enzyme immunoassay) is often used in hospital laboratories as a quick way to diagnose patients with potenially risky dieseases like influenza, so that medication may be quickly administered.
Using only the rapid EIA for the detection of Flu has always been considered a risk and was generally backed up by viral culture and/or PCR. However, with the increasing number of emergency room visits and the high strain on the healthcare system many hospitals are relying on tests that are inaccurate, and could ultimately have up to a 50% fail rate.
This is a pretty decent article on the dangers of diagnoses on rapid tests alone, but it does not get into the nitty gritty like we like here, of course the best resource is the CDC published guidelines which is presented here http://www.cdc.gov/h1n1flu/guidance/rapid_testing.htm.
Wash your hands while singing Happy Birthday!
Sneeze into your arm!