In certain embodiments, the disclosure provides an inflatable bladder lid that configures with a cartridge configured for assay testing. The inflatable bladder provides substantially uniform pressure to the cartridge. The pressure is substantially distributed across the one or more regions of the cartridge to extend pressure over a wide cartridge surface. At least a portion of the bladder lid may comprise a flexible membrane material that inflates and stretches over at least a portion of the cartridge to conformally contact its first/top surface.