Hi Richard
Firstly, I'm not a Histopathologist so be gentle!
We have a Telepath system and an HL7 interface with ICE.
I have only configured ICE for GP requesting so far. This is only used for skin biopsy type stuff, nothing too complicated but I think thats the only way you can go with Histo.I could not think of a way to get this working in the same way Chem/Haem works so I went for the basic approach. The diversity of the sample types within Histo make it virtually impossible to cater for everything and as you say, the list would be so large, a requestor would lose the will to live trawling through it.
I created a single test for a skin biopsy and then attached a rule in the form af a free text box asking for the full description of the sample. That basically is it. The data comes through and populates the Specimen type field and leaves the lab to manually amend the exact details of the sample and add the clinical details. In essence, it is really electronic PID and an assurance that you receive a legible form completed with all the details you require. Not perfect, but better than we were getting :-)