Patent ID: 6951631

Claim:
A test kit for determining qualitatively or quantitatively the presence of an analyte in a fluid sample, said test kit comprising; an assay device, said assay device having a detection zone, wherein the presence of the analyte in the fluid sample is indicated by accumulation of a labeled reagent within the detection zone; and (b) a reading device effective to detect labeled reagent, said reading device comprising means for initiation of the reading device to detect labeled reagent in the detection zone, wherein the means for initiation of said reading device comprises a switch actuator, and wherein said assay device comprises a contact portion, said contact portion and said switch actuator engaging in a lock-and-key engagement, wherein the reading device further comprises means for pressing an assay device inserted into the reading device against the switch actuator, wherein the reading device further comprises a cam that deflects the assay device away from the switch actuator unless the assay device is correctly positioned within the reading device, wherein the assay device is elongate, and wherein the reading device has a slot into which the assay device is at least partially inserted through a mouth for reading of the assay device, and wherein the slot has at least one projecting lip portion extending over the mouth of the slot, said lip portion acting to retain the assay device within the slot when correctly positioned therein, wherein said means for initiation of the reading device engages the assay device in a lock-and-key interaction, thereby forming a lock-and-key interaction between the reading device and the assay device whereby the reading device is initiated in response to and only when said assay device is properly positioned in lock-and-key engagement within said reading device and the lock-and-key interaction is formed.