its a little bit of all your answers, i think...
yes, there is a huge backlog of cases in some offices. One office I rotated at the backlog was MONTHS, another office the backlog is 30 days. interesting, because both are in very large cities, so the caseload is roughly equivalent. also interesting, because the office that was backed up for months appears flush with money, where as the office with the shorter backlog is vastly underfunded. not sure what's going on there.
also, depending on the methodology that is being used and what substances are being looked for, extra extractions and manipulation of the sample may be required. remember not all cases have a nice venous blood sample/urine sample with which to screen. in the less "fresh kills", tissue samples might be all you've got. also, i would think the interpretation of the results takes a lot more time than live patients. you may need to look at levels in multiple sample sources and take into account the levels, any effect that post-mortem interval may have had on the level, and any underlying natural disease that could have rendered the individual more susceptible to that drug. it's not as simple as it is in the ER when you get a +UDS for cocaine...
ALSO, if you are looking for something and the mass spec of that compound isn't in your library... you're not going to find it and you may have to find some of the compound and run it first. but this is probably not an issue with most drugs.
i know in NYC they rushed out Heath Ledger's tox in a week or so. definately possible to get complete results in that time frame. not sure what the real "backlog" is in that office (ask me again in July 2010😀) but i'm sure its longer than that. I guess different offices have different policies on the VIP cases re: jumping their tox to the head of the line
