If your child insists his positive drug-test results are a mistake, there's a chance he could be telling the truth.

Drug tests generally produce false-positive results in 5 percent to 10 percent of cases and false negatives in 10 percent to 15 percent of cases, new research shows.

Eating as little as a teaspoon of poppy seeds - less than the amount on a poppy seed bagel - can produce false-positive results on tests for opioid abuse, according to Dr. Dwight Smith, of the Veterans Affairs Medical Center in Black Hills, S.D.

cbsnews.com