Toxicology is necessary to determine cause and manner of death. Vendor will provide toxicology services for all Arapahoe County Coroner’s cases, to include alcohol, drugs of abuse and prescription medication screening and confirmation with blood and other fluid/tissue or specimens within eight (8) weeks of notification.
The selected laboratory must perform forensic toxicological analyses for the presence or absence of drugs (both therapeutic and illicit), poisons, and other xenobiotic compounds in fluids and tissues obtained at an autopsy for the purpose of assisting Medical Examiners and Coroners in establishing cause and manner of death. The laboratory must be certified by the State of Colorado Department of Health (CDPHE) to perform postmortem analyses. The selected laboratory must also be certified by the National Association of Medical Examiners (NAME).
The laboratory must be able to show it has an excellent record working on postmortem cases, and therefore, the vendors analytical procedures must be developed for these types of samples which may include putrefied, clotted, or minimal amounts of blood or tissue, or other less than pristine conditions.
All cases must be screened for the presence of ethanol and related volatiles (acetone, methanol, and isopropanol) by gas chromatography-flame ionization (GC-FID) headspace in the blood sample (if available). If an alcohol is present, vitreous, urine, or other fluids are analyzed and quantified by the same method to help establish absorptive or post-absorptive states and to rule out ethanol produced by postmortem fermentation. MVAs and homicide blood alcohols are quantified in duplicate when possible.
When urine samples are available, an ELISA immunoassay screen must be performed for the presence of opiates, barbiturates, benzodiazepine metabolites, methamphetamine, amphetamine, cocaine metabolite, propoxyphene, methadone, THCCOOH (marijuana metabolite), and tricyclic antidepressants. Urine samples must also be extracted and analyzed by gas chromatography-mass spectrometry (GC-MS) for the presence of other drugs and compounds not detected by immunoassay screening; this includes many therapeutic drugs including over-the-counter medications, SSRIs, anticonvulsants, etc. The GC-MS analysis of the urine sample also is used to attempt to confirm and identify any positive immunoassay screen results.
If urine is not available, blood, bile, or tissue homogenates are screened by ELISA immunoassay for the presence of opiates, barbiturates, benzodiazepine metabolites, methamphetamine, cocaine metabolite, propoxyphene, methadone, tricyclic antidepressants, and oxycodone. These samples must also be extracted and analyzed by GC-MS for drugs and compounds not screened by immunoassay screens and to confirm and identify the presence of positive immunoassay screens.
When a forensically significant drug or compound is encountered, quantification in blood or other relevant sample must be performed, generally by a GC-MS, using NIST certified standards, when available, and deuterium labeled drug analogues as internal standards when available. Generally, when a drug is quantified, the pharmacologically active metabolite of the drug must also be quantified. Analysis of atypical samples - brain, liver, gastric contents, etc. - may be performed upon request, to help interpret the significance of blood drug concentrations.
Upon request, atypical analyses - carbon monoxide, cyanide, heavy metal screening - must be performed on relevant samples.
All cases must have chain of custody documentation generated upon receipt for describing amount received, amount used in analyses, analytical personnel, condition of sample, etc. Every attempt must be made to use as little sample as possible while ensuring that accurate and reliable results are obtained.
Upon completion of testing, samples must be stored at -20º C to preserve their forensic value for at least twelve (12) months. If samples need to be stored indefinitely, notification will be made in writing. Written reports must be sent via fax and by mail when testing is complete. All instrumental data used to derive results must be retained indefinitely.
The selected vendor must be available for interpretation and telephone consultations with the Arapahoe County Coroner’s Office staff and must be willing, if subpoenaed, to provide expert testimony in an Arapahoe County Coroner’s Office / 18th Judicial District court case regarding toxicology tests they have performed. If the vendor is asked to testify, the County will give the vendor 24 hours’ notice.
