Heart rate characteristics index in cases of septicemia compared with risk factor-based probability of sepsis. In evaluating a new risk marker, it is important to compare its diagnostic utility with standard risk indicators. In this graph, average heart rate characteristics (HRC) index is shown for all cases of late-onset septicemia (LOS, >3 days of age) in infants in the randomized trial of HRC monitoring. The HRC index (solid line) rose prior to the clinical diagnosis of LOS (day 0, arrow). For comparison, probability of sepsis based on known risk factors of gestational and postmenstrual age, birth weight, and mechanical ventilation is shown for infants in the trial undergoing conventional monitoring (dashed line).