How bad is a false positive on an employment drug test?

Bring your scripts to the testing site with you. They would absolutely completely disregard a positive test if your known to be prescribed a medication that often causes false positives. That women was wrong, and completely unnecessarily rude. Do not take what she says to heart, it is clear she is just a bad employee. Technically, the Klonopin is not a false positive, it's just perfectly fine to test positive for benzodiazepines if you have a medical prescription. Just alert them ahead of time that you take ritalin & klonopin so they can right away be prepared for false positives.