The city Health Department has reportedly found that 9 percent of girls in three Brooklyn high schools and two other city schools tested positive for sexually transmitted diseases.

According to a New York Post report, health officials tested students in schools in neighborhoods with high STD rates. The city offered 1,800 students the voluntary and confidential testing and a little over 1,000 submitted urine samples. The Post reports that the students who were infected with Chlamydia or gonorrhea were given antibiotic treatment.

The school testing came after the city found high rates of Chlamydia in health clinics. Health officials hope to make the STD testing available to 30 schools across the city next year.