I normally just do 24 hours, but wishing I had put 48 hours for extremely contagious and awful things like gastro! Today I had a parent bring her child after having had gastro over the weekend...it had been 24 hours since his last symptoms, but 1/2 hour after he arrived, he had diarhea and seemed very fussy so I had to send him home. Praying now that he didn't spread it while he was here!