I have been practicing pediatrics since 1994. When I started in practice, a rapid strep test was done in the office and an culture test was done on the negative (no strep found) rapid tests to confirm whether strep was there or not. This culture took 1-2 days to get the results. A few years ago, we and most practices in Central Ohio switched to doing the over-night tests at Nationwide Children's Hospital that was completed by the next morning, so we would know for sure if the child has strep by the start of the next office day. One of the on-going issues with the Nationwide Children's test has been the expense.
As of April 4th, 2017 we are now doing an in-office DNA probe test for strep. It takes a few extra minutes, we swab the throat in the same way (although the swabs may be a little different), and it eliminates the need to do an overnight test. We believe the insurance coverage will be good, and in fact it will be cheaper if the previous overnight test would be needed. We like that the results are available right away, where for years we have called families the next day to tell them the overnight test was positive for strep. This delayed getting back to school (and parents back to work). Now we will know a definitive "Is it strep or not?" in about 8 minutes.