A method for detecting the presence and severity of illness, the effectiveness of treatment interventions, and the ability to change treatment to be more effective or aggressive, to optimize outcomes, to limit morbidity and mortality, and to illustrate a patient's prognosis, including the steps of using whole body impedance analysis to measure a patient's resistance, reactance, phase angle, and related electrical values at a healthy baseline, and thereafter in relation to the patient's complaints, evaluating temporal or progressive nature of negative values or diminution of the measured values of resistance, reactance, phase angle, and related electrical values over time.