The death of Whitney Houston made me wonder why it takes several weeks for drug and alcohol toxicology reports on a dead person. In a hospital or clinic, a blood-based drug screen can be done in minutes to hours. I can't imagine what would change after death that causes it to take weeks.

The death of Whitney Houston made me wonder why it takes several weeks for drug and alcohol toxicology reports on a dead person. In a hospital or clinic, a blood-based drug screen can be done in minutes to hours. I can't imagine what would change after death that causes it to take weeks.

— Tom, via email

The Los Angeles County coroner said Thursday, March 22, that Whitney Houston died from a combination of drowning, heart disease and cocaine.

That's 40 days after the songstress was found dead in her Beverly Hills hotel. As a team of inquiring minds, we know that kind of wait for answers can be agonizing, so we sought to learn why.

"It takes four to six weeks," Jackson County Deputy Medical Examiner Randy Arnold said, adding that the delay isn't at the county's end. "We ship it in just a couple days, usually."

Arnold said toxicology tests are done on possible homicides and cases where there is reason to believe drugs are a factor. The county sends samples to the Oregon State Police Metro Lab, one of two toxicology labs in the state, and the only lab in Oregon that does post-mortem toxicology investigations.

That led us to Tom Barnes, lab director for the Oregon State Police Portland Metro Lab.

Barnes said the lab does an initial test with blood and urine samples to see whether narcotics are in the system and, if so, what kind and in what amounts.

"The process itself takes weeks if it's positive," Barnes said. "Post-mortem they're looking for anything that's there."

Barnes said that even something as innocuous as aspirin can be deadly in high doses, so the levels of everything in the system are tested. Barnes said each of those facets can take hours or days to analyze.