If your child was sick at school how sick do you think they should be before the school calls home?

Any time a student is sent to or shows up at the infirmary (do they still use that word?) a parent should be notified immediatly. The parent will know more health data about the child than the nurse would and maybe the parent thinks the nurse is incompetent. The parent can decide what to do from there. This also helps protect the school from a liability point.