Ms. Laurel J. Farrell retired in 2007 after 30 years of service with the State of Colorado and is currently an independent consultant. Ms. Farrell worked for the Colorado Department of Public Health and Environment for over twenty-one years serving in a variety of capacities in the toxicology and breath alcohol programs. She then transferred to the Colorado Bureau of Investigation and was an Agent-in-Charge for the Denver Laboratory when she retired. In this capacity she had supervisory responsibility for a number of the forensic disciplines performed in the laboratory. Ms. Farrell is an active member of the Society of Forensic Toxicologists where she served for seven years as an officer/director, including as President in 2002. She is a Fellow of the American Academy of Forensic Sciences and in 2008 received the Toxicology Section Ray Abernathy Award for Outstanding Forensic Toxicology Practitioner. Currently Laurel is active in laboratory accreditation/certification programs through two organizations. She is a Staff Inspector for the American Society of Crime Laboratory Directors Laboratory Accreditation Board (ASCLD/LAB) and also serves as a laboratory inspector for the National Laboratory Certification Program (NLCP) of the Department of Health and Human Services Substance Abuse and Mental Health Services Administration (SAMHSA). The training provided by Ms. Farrell, in this course, is based upon her own personal experience and is not presented as a representative of or spokesperson for ASCLD/LAB or NLCP.