I have never taken methamphetamine or MDMA. In the last 2 years I have tested positive, 3 times always faint line roadside and lab tests come back just inside the cut off level. Why would this happen? I cannot find anything to explain why? It has ruined my life. I have lost my licence and cannot work as a registered nurse. Yet I have never taken drugs. Has anyone else ever had this experience? I am at my wits end. I am about to appear before a magistrate on the 30th of March. I want to plead not guilty as I did not knowingly take drugs but how can I prove this?