The Toxicology Section of the Mississippi Forensics Laboratory provides analytical testing services for the state’s law enforcement agencies for death investigations and criminal cases. Analysis of biological specimens for the presence of alcohol, drugs, and other toxins is performed to determine cause and manner of death, as well as for cases involving driving under the influence (DUI) and impairment. Other cases, such as aggravated and sexual assault and other miscellaneous charges, are also submitted for Toxicology analysis.
Biological specimens including, blood, vitreous fluid, urine, bile, stomach contents, and organ tissues, collected during autopsies by the State Medical Examiner’s office and state Coroner’s offices, are submitted to the Toxicology Section for analysis. Presence of alcohol and/or drugs may aid in determining the manner and cause of death or indicate involvement in criminal activity resulting in death. Deaths involving alcohol and/or drug use include fatal overdoses, traffic related fatalities, drug-related homicides, unexplained deaths and suicides.
Toxicology analysis is also performed for cases involving Driving Under the Influence of alcohol (DUI) and Driving Under the Influence of Drugs (DUID). Alcohol is a central nervous system depressant that, even at very low concentrations, causes effects such as impaired judgement, increased reaction time, impaired motor function, decreased coordination, and impaired ability to multi-task, all of which are crucial for safely operating a motor vehicle. For individuals 21 years of age or older, a blood or breath alcohol concentration of 0.08% or greater, in the state of Mississippi, is considered prima facie evidence of impaired driving while under the influence of an intoxicating beverage.
Drugs of abuse, both prescription and illegal, can also impair one’s ability to safely operate a motor vehicle. The Toxicology Section performs testing of blood and urine specimens to detect illegal substances, such as marijuana, cocaine, PCP, MDMA, and methamphetamine, as well as prescription medications, including opiates, benzodiazepines, antidepressants, and barbiturates. While statutory limits of these substances are not currently established in the state of Mississippi, use of drugs and their presence in biological specimens can reduce an individual’s ability to safely operate a motor vehicle.
Scope of Analysis
Analysis of biological specimens is performed to detect and determine the quantity of alcohol and other volatiles present in case samples. Headspace gas-chromatography is used to test for ethanol, the alcohol found in alcohol beverages, as well as methanol, isopropanol, and acetone. Beverage alcohol analysis is also performed to determine the alcohol concentration of fluids suspected to contain ethanol. These liquids are often recovered from vehicles or have been confiscated from prisons.
Specimens submitted to the Mississippi Forensics Laboratory for drug analysis undergo an initial screening process to determine what types of drugs and drug classes may be present in a sample. Blood specimens are screened using the Enzyme Linked Immunosorbant Assay Technique (ELISA) and detect the following drugs and drug classes: amphetamines, barbiturates, benzodiazepines, buprenorphine, cocaine, cannabinoids (THC), dextromethorphan, fentanyl, meprobamate, methadone, methamphetamine, opiates, PCP, tricyclic antidepressants, tramadol, and zolpidem. Urine specimens are screening by Enzyme Multiplied Immunoassay Technique (EMIT) for amphetamine/methamphetamine, barbiturates, benzodiazepines, cocaine, cannabinoids (THC), methadone, opiates, PCP, propoxyphene and tricyclic antidepressants.
Results from the screening procedures are preliminary and require more specific confirmation testing to further identify any drugs present in a sample. The samples undergo an extraction process which involves subjecting the specimens to a series of solvents and buffers which remove biological matrix impurities and isolate drugs in a solution suitable for analysis on analytical instrumentation. Confirmatory analysis is performed by gas chromatography with a mass spectrometry detector (GC/MS) or liquid chromatography with a mass spectrometry detector (LC/MS/MS). These types of instrumentation give analysts more specific structural information about any substances detected in a sample so that they can be identified.
Carbon Monoxide Analysis
Carbon monoxide (CO) analysis is performed for death investigations that involve cases such as house or automobile fires, or other instances where death from CO inhalation is suspected. Carbon monoxide is a colorless, odorless gas produced by burning of fuels such as coal, wood, charcoal, oil, kerosene, propane and natural gas and is also produced by cars, generators, and lawn mowers. Inhalation of CO prevents oxygen from reaching the heart and lungs and can be fatal. CO poisoning can occur accidentally or intentionally as means of homicide or suicide. The Toxicology Section performs CO analysis by Co-oximetry in blood specimens to determine the carboxyhemoglobin concentration. A normal adult will have a carboxyhemoglobin concentration of around 2% or less (about 10% in smokers). Higher levels of carboxyhemoglobin can cause dizziness, confusion, nausea, and death. The absence of carboxyhemoglobin in a blood specimen indicates that the individual had died from a cause other than CO exposure.
The Toxicology Section also accepts miscellaneous items for non-routine testing for unknown suspected poisons. This type of testing poses a unique challenge due to the type of material or substance submitted for testing, as well as the wide range of drugs or poisons that could be present in the substance. When agencies submit these types of cases, it is crucial to include as much information as possible as to the specific drugs and/or poisons suspected to be present. When possible, submission of a sample of the agent or material suspected to have been used as the poison aids in performing comparison analysis for identification of unknown substances.
The Toxicology Section is comprised of 10 Forensic Scientists with backgrounds including Bachelor of Science and Master of Science degrees in scientific fields such as Toxicology, Chemistry, and Forensic Science. After undergoing an extensive training program at the Mississippi Forensic Laboratory, analysts are certified to perform independent casework in alcohol and drug analysis, as well as to testify in courts of law and give expert opinions on the effects of alcohol and drugs as related to death investigations and performance impairment.
Continuously changing drug trends and synthetically produced substances pose a constant challenge for Toxicologists in the detection of designer drugs and new drug analogues. New substances require extensive method validation and development of analytical procedures to identify these substances. It is the mission of the Mississippi Forensics Laboratory to stay current on emerging drug trends, forensic toxicology research studies, and state of the art instrumentation in order to provide the highest quality and thorough testing options to its customers.
Gulf Coast Lab
Section Chief- David Lockley