Would zoloft (sertraline) make you fail a drug screen?

No: This is for a common workplace drug screen, correct? I hope you are taking it under a physician's supervision. It is not a drug of abuse, and even if it were, if you have a prescription you should be fine. You cannot taking medications like this and be a private pilot, and you might conceivably be screened for this in the event of a mishap. Best wishes.