Systems and related methods are provided for measuring a ketone in the fluid of a patient or other user. The systems include a portable measurement device for analyzing a plurality of fluid samples and for generating a corresponding plurality of ketone measurement results. The systems also include an electronic or communications device, for example, such as a cell phone or smartphone, configured to communicate with the measurement device. The system further includes a software application. The systems and related methods according to one aspect provide reminders, preferably interactive reminders that facilitate user compliance with a weight management or diabetic ketoacidosis (DKA) monitoring or prevention program. The systems and related methods according to another aspect incorporate ketone tags and/or trigger points to improve accuracy of results and to advance user compliance.