The invention provides a medical device system comprising at least two technologies wherein at least one technology is based on bio-impedance measuring and/or at least one technology is based on spectrophotometry measurements wherein software cross analyses the results to assess the homeostasis of an individual. The technologies measure a variety of parameters. In one embodiment the bioimpedance measuring equipment measures in bipolar mode and in tetrapolar mode and the spectophotmeter measuring equipment comprises a pulse oximeter. The system and homeostasis score can be used to determine and monitor therapy for a patient.