Disclosed herein is a non-transitory computer-readable media having computer-executable instructions thereon. When executed by the processor of a mobile computing device, the computer-executable instructions cause the processor to display a pairing screen that instructs a user to wirelessly communicatively couple the mobile computing device to a GFR sensor, display a sensor placement screen that instructs the user to place the GFR sensor on a body of a patient, display an injection screen that instructs the user to administer a GFR agent into the body of the patient； transmit a signal from the mobile computing device to the GFR sensor to cause the GFR sensor to initiate collection of light absorbance data for calculating a GFR of the patient； receive light absorbance data from the GFR sensor, and store the received light absorbance data.
