Hi, my husband smoked weed and had positive test at work, he has completely stopped around 8 weeks ago, he went back to work after a negative test, he was given another test and it came back positive! I know he hasn’t smoked, why has this happened? He takes ibuprofen for a painful elbow, could this give a positive reading? He’s been dismissed and can appeal but we are at a loss as to what to do. Thank you