GRAND RAPIDS, Mich. (WOOD) — How sick is too sick for school?

In a national poll released Monday by the University of Michigan C.S. Mott Children’s Hospital in Ann Arbor, 75 percent of parents said their child had stayed home from school because of illness at least once during the last year. But the survey also found that parents are split and often confused about when to send their kids to school and when to keep them home.

“In my house, we never even had a thermometer because I didn’t really care what the number was. I more cared what the child looked like,” Dr. Dan McGee of Helen DeVos Children’s Hospital said.

However, appearances can be tricky because the problem is sometimes psychological.

“I think every child in school has some stress, whether they admit it or not. You need to tease out how much of that stress is affecting their physical health, how much is affecting their mental health and how much is just they don’t want to go to school that day,” McGee said.

He said there are some basic red flags to look for: fever of 100.4 or above, runny nose and cough, and vomiting or diarrhea.

In the national survey, symptoms played a big role for parents. Most parents — 80 percent — were not likely to send a child to school with diarrhea, but significantly fewer — 58 percent — would keep a child home for vomiting. If the child had a slight fever but was acting normally, 49 percent of parents would not send them to school.

“If they’re lying around like a limp dishrag but their temperature is 99, I’m more concerned about that than a child running around the house beating up on his brother and has a temperature of 101,” McGee said.

Once the decision has been made to keep a child home, the challenge presents itself again: When to allow them back into school?

“I think you can use your child as a gauge, not necessarily have a magic number. If your child is up and running around and feels like he wants to go back to school, then send them,” McGee said.