A composite litter material for detecting a disease, such as urinary tract disease, when contacted by feline urine includes an absorptive polymer material forming a solid matrix, exfoliated clay embedded and dispersed within the solid matrix, a chromogenic indicator provided within the solid matrix, and an oxidizing agent distributed and stabilized within the solid matrix to be responsive to peroxidase activity in the urine to activate the chromogenic indicator. A method for detecting or diagnosing a feline disease includes contacting urine with the material and detecting a color change. A method of manufacturing the composite material includes preparing a mixture comprising the absorptive polymer and water and distributing the exfoliated clay, chromogenic indicator and oxidizing agent within the mixture, preferably by extrusion and addition of the components at particular points in processing the polymer mixture.
