A disposable, point-of-care diagnostic cartridge has a base with a reaction chamber and an inlet and a fluidic channel extending therebetween. An apparatus is fixed to the base. The apparatus includes a flexible upper layer having a reservoir containing fluid therein a flexible lower layer, and a rigid substrate sandwiched between the upper and lower layers. The upper layer is fixed to the substrate with a first adhesive having a first bond force. The lower layer has a valve member in fluid communication with a through port in the base and the base inlet. The valve member has a closed state to seal off the through port and the inlet from fluid communication and an open state to bring the through port and the inlet into fluid communication. The valve member is moveable from the closed state to the open state under a force less than the first bond force.
