FALSE POSITIVES

A recent editorial on drug testing for high school students cited the
trivial rate of 3 drug users out of 797 tested, and cited the high cost
paid in money and embarrassment. There is another issue, false positives.
False positives conclude a child is using drugs when they are not. The
food, medicine, herbal supplements or test error can cause false positives.
Proper testing quizzes the student about the various foods, medicines, and
herbals to eliminate improper results. False positives in the test are
another matter.

So how good are the tests? The literature says 3 to 40 percent false
positives, particularly when the subject is not quizzed about foods and
medicines. If for 797 students the false positive rate was 1 percent, then
all three guilty would be found and eight innocents would be accused.

Parents need to demand to know if the students are properly quizzed to
eliminate the food, herbals and medicine issues and parents need to know
the testing false positive rate.

David Cornell

Houston, Texas