How toxicology testing determines which drugs killed overdose victims

Deputy coroners who respond to death scenes learn to spot the signs of an opioid overdose, but their trained assessment isn't enough to certify a cause of death. There needs to be proof.

Proving the presence of drugs in the systems of the deceased calls upon a process called toxicology testing that hinges on a minutes-long spin in a centrifuge-like device but turns into a weekslong series of events involving coroners, shipping companies and out-of-state scientists in private labs.

Basic testing costs coroners $185 for each case, but the price can rise to almost $500 if officials need to add a special panel that detects the presence of synthetic opioids. Coroners say these drugs, including imitations of the powerful painkiller fentanyl, increasingly are penetrating the suburban supply as black-market chemists create new concoctions that are potent and cheap.

Last year, coroners and medical examiners in the six-county area ordered toxicology testing on 6,606 cases, up from 6,463 in 2015 and 5,850 the year before that.

The growing need for screening to determine which drugs killed a person has coroners and labs working at full tilt to test and solve each case. Here's how the process works, according to McHenry County Coroner Anne Majewski and Dr. George Behonick, director and chief toxicologist at AXIS Forensic Toxicology in Indianapolis.

Step 1: The scene

Deputy coroners look for paraphernalia related to a drug overdose, such as white powder in a baggie, a spoon, needle, syringe and tourniquet. They also check for physical signs of overdose, such as respiratory depression and fluid coming out of the mouth.

Step 2: The decision

The coroner decides whether to conduct an autopsy. If so, the office orders one or more toxicology testing panels from a certified lab. Panels include a comprehensive drug screen, drugs of abuse, an extended list of drugs of abuse, synthetic cannabinoids and psychoactive substances, among others. The psychoactive substances panel finds synthetic opioids such as fentanyl analogs.

Step 3: The samples

During the autopsy, forensic pathologists gather blood, urine and samples of a fluid from the eyes called vitreous. They send the specimens via secure next-day shipping, usually to one of two facilities: AXIS Forensic Toxicology in Indianapolis or NMS Labs in Willow Grove, Pennsylvania.

Step 4: The arrival

Toxicologists inspect each specimen that arrives, inventory it with a specific number and verify demographic information about the decedent. They group specimens into batches for testing using separate procedures that check for substances such as opiates, synthetic opioids, alcohol, cannabis and cocaine.

Step 5: The testing

Labs use a machine called a liquid chromatograph - mass spectrometer, or an LC-MS for short, to separate out each substance within the blood, urine and vitreous specimens and determine the chemical identity of each component. (Behonick calls the machine "the gold standard for doing analytical work to identify compounds." To buy, install and operate each one costs in the hundreds of thousands.)

The scientist running each test calibrates the machine to ensure quality control and follows testing procedures that have been validated for accuracy, precision, specificity and sensitivity. Run times for each test are only minutes. AXIS employees work in overlapping shifts until midnight five days a week to test specimens as quickly as possible.

Step 6: The answers

A data-certifying scientist goes over all testing data to ensure it meets acceptance criteria. Then a toxicologist performs a final case review before results are released to the client. AXIS aims to report results within 10 to 14 business days of receiving each specimen. Coroners often estimate to the public that the process can take longer, up to four to six weeks.