The only thing that matters is for your results to say "RT-PCR" on them. PCR testing has gotten faster and more flexible over the past several months. Now I haven't seen a 15-minute turn around for PCR - they must have a lab onsite or something, but if your results say PCR on them then you are good to go. Sometimes it's hidden in the wording on the test, so have the clinic highlight it if you don't see it right away.