Forensic chemists analyze drugs submitted by other agencies. Drug types received commonly range from clandestine chemical substances to therapeutic or prescribed medications. Cocaine, heroin, marijuana and amphetamines, all drugs of abuse, represent the most common products received for chemical assay. Law enforcement agencies within the medical examiner’s district are faced daily with the challenge of identifying drugs found subsequent to an arrest or search warrant execution.
An intoxilyzer instrument provides an objective, scientific means of testing someone, who is suspected by police to have been driving under the influence of alcohol, by measuring a sample of the suspect’s breath for determinable levels of alcohol concentration. Grant funds supplied by the Texas Department of Transportation were used to establish the ME office’s intoxilyzer program in 1994. Under the program, forensic chemists establish intoxilyzer test sites, calibrate and maintain equipment and train intoxilyzer operators, which benefits local police agencies as well as citizens.
Forensic toxicological services were established at the Medical Examiner’s Office in 1983. Subsequently, the toxicology laboratory has expanded to include mass spectrometry, gas chromatography and high-pressure liquid chromatography analysis. The toxicology laboratory provides drug testing to assist medical examiners in determining the cause and manner of death by isolating, identifying and determining the level of chemicals in collected specimens. Additionally, the forensic toxicology laboratory participates regularly in established analytical proficiency testing and quality assurance programs.
Dr. Johnson graduated from The University of Oklahoma with a Ph.D. in Analytical Chemistry in 2004. Certified as a forensic toxicologist by the American Board of Forensic Toxicology, he joined the medical examiner's office in 2011. Additionally, Dr. Johnson is active in several professional societies including the Society of Forensic Toxicologists, the American Academy of Forensic Sciences and the Southwestern Association of Toxicologists. He has published over 50 scientific articles in his career all of which deal specifically with forensic toxicology.
A copy of the current Laboratory Services Handbook may be downloaded using the following link:
County Telephone Operator 817-884-1111
Tarrant County provides the information contained in this web site as a public service. Every effort is made to ensure that information provided is correct. However, in any case where legal reliance on information contained in these pages is required, the official records of Tarrant County should be consulted. Tarrant County is not responsible for the content of, nor endorses any site which has a link from the Tarrant County web site.
This site is best experienced with supported browsers: Internet Explorer 9 and above, Google Chrome, Mozilla Firefox, or Apple Safari. If you use an older or unsupported browser, you might notice that some features do not function properly. Click the browser name above to learn more about the recommended browsers.