Why does toxicology take so long?

In several of these celebrity deaths in which drugs are thought to possibly be a cause, they always say the toxicology reports could take 6-8 weeks.

What happens if a person is brought into an ER, still alive, but the doctors suspect some kind of overdose or poisoning, and they need to know ASAP?

I wonder if the best, most accurate tests just happen to take several weeks to play out. Like maybe waiting to see it certain types of crystals grow in the presence of testing agent X, or something.

Tox labs are often so overwhelmed by the ASAP types of emergency room cases that lower priority autopsy-like cases are pushed back. I had a friend that used to work in the toxicology department of the lab where I used to work, and everyone in the lab was on call at all times. She used routinely to be called in in the middle of the night two or three times a week.

Could it have something to do with the fact that a live person will display certain symptoms and may be able to answer questions?

If a lab just gets a blood sample and no idea of what to look for they have to check for, well, everything. It may also be that it doesn’t take 6-8 weeks to test a given blood sample but the labs tend to have a long waiting list - maybe it only takes 1 week but that week is two months down the road.

That makes sense. So I guess it’s not necessarily a different type of test, but just a matter of priority at the lab.

Thanks

Just an update: Finally someone asked this of a doctor on TV. The doctor confirmed pretty much what was suggested earlier. Emergency toxicology can be done in a matter of a couple of hours. When there’s a death, there’s no rush, obviously, but they also want to examine the tissues and organs to determine how long the drugs were being taken, at what levels, etc., so that takes a little longer, in addition to the backlog in the labs.