Yeah, I've read a few things and thought about IgE testing a few times, and apparently it can be successful with postmortem specimens -- including antigen-specific IgE testing. I don't know what the real-world cost would be, but if you don't even have a potential antigen then you'd have to do a panel and simply hope to get a positive somewhere. I'm not sure what the false pos/neg rates are, either. But total IgE and even tryptase are reportedly not particularly specific, especially as the postmortem interval prior to obtaining a sample increases, and there may be some stability issues in storage.
I've always been a little dismayed at how many things are state/local/office/personal training specific when it comes to either accepting jurisdiction or assigning manner of death on certain cases, but many such differences are so ingrained as to be essentially impossible to nationally standardize -- at least not in a single generation of forensic pathologists. There are very valid arguments posed on each side of things like this, but generally as long as an office is consistent over time the different approaches don't seem to pose significant problems (other than some offices taking jurisdiction over significant numbers of certain health care related deaths they deem "accidents" while other offices deem them natural by way of complication of therapy for a natural disease process...blame the helper or don't, I suppose). Currently I take the view that 1 bee sting wouldn't kill an otherwise healthy individual but for an internal "natural" allergic reaction, while 100's of stings might kill as an external factor. Others may argue that if a homicide by heart attack when someone threatens with a gun is still a homicide in a susceptible person (e.g., AS&HCVD), even though showing off a gun doesn't typically kill normally healthy people, then a single bee sting is similarly comparable to 100's as an external factor in the death. Then there is the asthmatic who has yet another attack after..running? a bit of a cold? high pollen/mold day? stepped into an old cabin with lots of dust?...and dies of asthma, which we generally assume has some sort of trigger perhaps common to any environment, but still technically "external". I tend to think that if something is an accepted part of daily living -- common dust/pollen, perhaps a single ant bite or bee sting, mosquito bite, etc., then complications related to it is probably natural. But I do like to hear people's reasons.
There is reason, I think, in the different approaches. One just needs to be able to explain theirs in hopefully a consistent fashion.
