Alcohol Abuse Health Center

The Truth About Toxicology Tests

Why do the forensic toxicology tests take so long?

Getting a complete and accurate forensic toxicology test result can be a lengthy process for a variety of reasons, according to the College of American Pathologists and experts interviewed by WebMD.

There may be a lot of specimens that need to be tested, which means more testing time. And as an investigation proceeds, information about the possibility of another drug being involved may surface, so even more testing may be needed.

When the first round of positive tests have to be confirmed by the more sophisticated method, this may require sending out the specimens to more specialized laboratories. And that adds to the delay.

"Four to six weeks is pretty standard," Magnani says of the time line for forensic toxicology testing. Besides the time needed for painstaking analysis and confirmation, she says, there could be a backlog of tests that need to be done at a particular laboratory.

"Each one should be handled thoroughly, whether they are a celebrity or not," she says.

How do the toxicology reports help determine cause of death?

Experts look to see if the concentration of drugs or poisons are in the toxic or lethal range, Magnani says. They take into account other information, such as symptoms before their death.

For instance, she recalls a man who passed out and when roused by police was so belligerent it took several officers to subdue him. Then he died suddenly.

No physical findings from the autopsy pointed to a cause of death, she says. ''The toxicology report showed the presence of cocaine at a level sufficient to cause death," she says. And the belligerent behavior was another clue.

But not every toxicology report is so clear-cut, Robin says. And television really does present a skewed view of forensic toxicology testing, he and other experts agree.

"At the end of the [TV crime] show, they don't say it's an indeterminate cause of death," he says. But in real life? "Two to five percent of deaths are indeterminate," Robin says, citing forensic literature.

What complicates the process? Drugs of abuse can change constantly, Robin says, with one drug becoming popular, for instance, while others fade in popularity. "You are always looking for what is the new drug [of choice]," he says.