An instrument includes a fluidic cartridge having a body comprising a malleable material and a layer comprising a deformable material bonded to a surface of the body that seals one or more fluidic channels that communicate with one or more valve bodies formed in a surface of the body. The valve can be closed by applying pressure to the deformable material sufficient to close off a fluidic channel in the body. A cartridge interface is configured to engage the cartridge.