How long should it take to set up/take down a portable alchemy lab? My players are in the middle of a city combat, and they have just suffered a poison attack, and the alchemist logically wants to identify the type(s) of poison being used. Since it is a city combat the length of time is rather important, but the item doesnt say. When I envision the portable lab (or any alchemists lab) I see one or more tables with glassware set up in strange and complex configurations with multiple flames of different colours so you end up with your desired result.
For my games: It takes a short rest period in order to setup a crafting station and use it to do anything. Logically speaking, you can't fletch and sharpen an arrow in 5 minutes, you would need to setup tools and a work bench so a couple of hours would be required. The same goes for mending significantly torn garments, damaged armor, sharpening blades, brewing potions and creating traps.
Basically, if they don't have the time for a short rest, they don't have time to draw blood and perform the necessary titrations in order to identify a specific type of poison.
I mean, it seems nice to have the skill, but it's a crafting skill. That's not something you can do on the run or in the middle of a dungeon. If you're looking for a reason to give the players an answer to the alchemists question though, you could have them do a skill check based on survival, nature or heal/medicine in order to recognize any unusual symptoms that might also identify the poison.