Forensic Toxicology

Coroner and Medical Examiner Testing

 

The Forensic Toxicology section provides alcohol and drug analysis for county coroners and medical examiners to assist in routine death investigation. The section also tests specimens collected in the investigation of death occurring during the operation of motor vehicles, including boats, snowmobiles and all-terrain vehicles, as required by Wisconsin Statutes. The section tests approximately 3,000 specimens annually for coroners and medical examiners.

 

Blood Specimens

Fluoride-preserved whole blood is the preferred specimen for comprehensive drug testing. WSLH kit #33 and #34 contain an appropriate vial for securing this specimen. If these kits are unavailable, standard specimen collection tubes containing sodium fluoride/potassium oxalate may be used. It is desirable to collect 15-25 mL of blood, if possible, for comprehensive drug testing. When this volume of specimen cannot be obtained, an alcohol analysis alone may be completed with as little as 0.5 mL of blood. Minimal drug testing requires approximately 4 mL of blood. Other types of blood specimens (unpreserved whole blood, serum, plasma) can be tested but are not recommended.

 

Urine and Other Specimens

Urine, vitreous, gastric, and other specimens may be collected at autopsy and forwarded to the laboratory for testing. The nature and volume of these specimens often determines what analysis can be performed. Urine and vitreous specimens are routinely tested for ethanol. Urine specimens are screened for the presence of drugs. Vitreous specimens are not screened but are used for quantitative drug determinations when specimen volume is sufficient. Gastric and other specimens are not routinely tested, but testing of these specimens is available upon request.

 

Order Collection Kits

Kits can be ordered using the Forensic Toxicology Coroner Kit Order Form.

 

How is the Testing Done?

Specimens submitted for toxicology testing are analyzed following forensic protocols. Specimens are initially tested for alcohol and other volatiles by direct injection gas chromatography. Specimens requiring drug testing are screened by immunoassay or chromatographic techniques. Those specimens that have positive initial screens are re-analyzed using alternate methods. Additional quantitative procedures may be required. The testing procedures detect prescription drugs, over-the-counter drugs, illicit drugs, and some drug metabolites. While these procedures will detect a broad range of drugs, some drugs cannot be detected with current WSLH methodology or are detected only by special procedures. A history of suspected drug exposure is helpful to ensure that all drugs of interest are monitored.

 

How are the results reported?

The results of the testing are reported by mail. Copies of the WSLH reports are mailed to the responsible county official. A copy of the report will also be mailed to the pathologist who conducted the autopsy upon request. Further release of the laboratory findings is at the discretion of the coroner or medical examiner.

 

Interpreting the report

 

Blood specimens

The blood ethanol concentration is reported in concentration units, grams per 100 milliliters (g/100 mL) of whole blood. Other drugs detected are reported either as “Present” (indicating that the drug was detected and confirmed but not quantitated) or as a quantitative concentration of drug, expressed as micrograms per milliliter (mcg/mL) or nanograms per milliliter (ng/mL). The report may contain therapeutic ranges for the drugs detected and/or additional comments. Where therapeutic ranges are provided, these ranges represent expected drug concentrations for all conditions where a particular drug might be appropriate. Post mortem changes in drug concentration can occur with some drugs, consequently, the report must be interpreted with caution.

 

Urine specimens

The urine ethanol concentration is reported in concentration units, grams per 100 mL (g/100 mL) of urine. In death investigations, the urine ethanol concentration is not converted to a corresponding blood ethanol concentration. Other drugs and drug categories are reported as “Not Detected” or “Positive” with specific drugs reported as “Confirmed.” Quantitative results are not available for drugs other than ethanol; however, cutoff concentrations for the drugs/drug categories are provided. There are no therapeutic ranges for drugs detected in urine specimens. The presence of a drug in urine indicates exposure to the drug but does not indicate impairment or toxicity due to the drug.

 

Other specimens

Results from other specimen types (bile, vitreous, gastric contents) require individualized interpretation. Please contact the laboratory for assistance.

 

Post-testing Concerns

 

Unexpected results

These may arise when the presence or absence of alcohol and/or drugs is reported when another result was anticipated. These may also include reports of unexpectedly or extraordinarily high concentrations of an analyte. As there can be a number of possible reasons for the laboratory obtaining results which you did not expect, please call the laboratory at 608-224-6241 to discuss your concerns.

 

Specimen availability

Specimens are discarded after six months. Specimens submitted to the Forensic Toxicology section are routinely retained for six months following the date of the final report. Specimens will be saved beyond this time upon written request from the submitter or subject. The specimens will be saved an additional two years from the date of the request. The WSLH cannot honor requests to save samples for indefinite periods of time.

 

Scope of Testing

The Forensic Toxicology section provides comprehensive testing for alcohol and other drugs, including many over-the-counter, prescription and illicit drugs. The fluoride-preserved whole blood recommended for drug testing is often not appropriate for other analytes or medical conditions. Specifically, testing for disease agents (HIV/AIDS, hepatitis, etc.), genetic testing (as for subject identity or possible paternity), and routine clinical chemistry testing (glucose, electrolytes, creatinine, etc.) frequently requires plasma, serum, or whole blood collected with a different preservative. If you anticipate that a death investigation will require testing in areas outside of toxicology, it is recommended that additional specimens with the appropriate preservatives and/or anticoagulants be collected. Submit these specimens directly to the laboratory that will perform the testing.

While the Medical Toxicology section does not perform these tests, the WSLH can provide information and testing for HIV/AIDS and hepatitis. Genetic testing for identity or possible paternity is not available within the WSLH. Routine clinical chemistry tests are often most efficiently performed at local hospitals and clinics.

 

Additional testing

Testing beyond routine drug and alcohol testing (for HIV/AIDS, paternity, or analytes not tested for at WSLH) may require additional authorization or the release of the specimen to outside agencies. Please contact the laboratory for assistance.

 

Where to get more information

Call the Forensic Toxicology section at 608-224-6241. Mailed correspondence should be addressed to:

Forensic Toxicology
Wisconsin State Laboratory of Hygiene
2601 Agriculture Drive
PO Box 7996
Madison, WI 53707-7996