ORLANDO, Fla. (AP) _ School officials have praised state Education Commissioner Betty Castor's guidelines on AIDS-exposed students, which aim to keep the children in classrooms unless they might spread the disease.

''I agree with what they've done. This gives us the backing of the state but leaves the final decision to home rule,'' said Barbara Ward, chairman of the St. Johns County School Board. ''I think it will be very well received.''

''I think the state department has taken a reasonable and logical step,'' said Richard Chapman, an associate superintendent for Orange County schools.

In Florida, 86 AIDS cases among people under 20 have been reported, said Deborah Holtzman, a state epidemiologist. No statistics are available on how many school-age children have tested positive for AIDS antibodies or who have AIDS-Related Complex.

Florida educators had pressed for state guidance after publicity about three AIDS-exposed hemophiliac brothers, whose parents had sued to get them into classes in Arcadia.

Louise and Clifford Ray won their federal suit, but protests, bomb threats and a school boycott followed the August enrollments of sons Ricky, Randy and Robert, who so far show no signs of the ailment. The Rays moved to nearby Sarasota a month later, after an arsonist torched their Arcadia home.

Castor's guidelines, issued here Thursday before some 230 educators at the Florida Conference on AIDS Education and Prevention, were criticized as ''nonspecific'' by one of the Ray family's lawyers, Bill Earl.

Danny Tew, president of the Arcadia-based Citizens Against AIDS in School, which protested the Ray brothers' school enrollment, also blasted Castor's guidelines.

''The government is taking rights away from local school boards,'' Tew said.

The guidelines do not carry the force of law, but are based on state and federal anti-discrimination laws, Castor said.

''The department is committed to enforcing the laws of Florida. If a district simply rejects all of the information ... and discriminates against a student, we will go to court,'' she said.

Infected children would be barred from classes only if they might pass the disease on to other students, she said.

Her guidelines call for each school district to establish a review panel for a thorough case-by-case analysis of students exposed to the AIDS virus, and to immediately incorporate education on acquired immune deficiency syndrome into the school curriculum.

Castor's department will ask lawmakers to add AIDS education as part of a life-management skills course required for high school graduation, and in health and science courses in middle schools, she said.