Technologies are generally described for indwelling medical devices for detection of luminal catheter colonization. A substrate for use as an indwelling medical device includes an elevated biofilm releasing medium including a dye for release into urine on the occurrence of an elevated biofilm build-up on the substrate in the urine and an elevated pH releasing medium including a dye on the substrate different from the dye used to detect biofilm build-up for release into urine on the occurrence of an elevated pH level in the urine. Methods of manufacture and use of the disclosed indwelling medical devices are also described.