We describe a system/method for predicting the outcome of a medical procedure on a patient. The system/method uses using complement cascade data representing levels of a set of complement cascade markers in the patient at a succession of peri-operative time intervals, determining deviations from a model of the response to provide a pre-symptomatic prediction of the outcome. In embodiments the complement cascade pathways include the lytic pathway and at least one of the lectin pathway, the classical pathway and the alternative pathway, and the biomarkers include at least C3. The system may include an electroluminescence or plasmon-resonance multianalyte detector to analyze a blood sample from the patient.