The invention provides disintegratable film compositions for diagnostic test devices. The films are prepared with a combination of components that yield films of sufficient film strength and desired disintegration profiles. A disintegratable film according to the present invention contains a water soluble high molecular weight component, a water soluble low molecular weight component, and one or more reagents for use in a diagnostic device. Optionally, the films further contain a starch component, a glucose component, a plasticizer and/or a humectant, and/or a filler. The invention further provides a diagnostic testing device, which includes a film according to an embodiment of the invention, and methods of using such devices.