Abstract: An assay tray assembly and an assay tray primarily for chromatographic analysis has a plastics moulded test tray 1 mounted on a plastics moulded collection tray 72, The test tray has a spaced array of chambers 3 disposed as per a microtiter plate, Each chamber has a bottom outlet port 5 formed by a flange 8 which retains within the chamber a chromatographic medium to which test liquid deposited in the chamber is to be subjected for the percolate or eluate liquid to emerge from the respective outlet ports, The collection tray 72 has a spaced array of wells 16 disposed as per a microtiter plate to correspond with the chambers 3 and the tray 14 is mounted on the tray 72 for each chamber to communicate with a corresponding well 16. Each chamber 3 has a tubular spigot part 12 which extends into the respective well 16 to alleviate cross contamination of the liquid derived from the outlet ports 5.