Observational studies have shown that most patients with non-infectious SIRS have an inflammatory-mediated procalcitonin level ranges from 0.3 to 0.8 ng/mL [57–60], while studies on septic patients (from any source) in an ICU setting have shown PCT levels range from 4.5 to 12.0 ng/mL [61–64]. Here, CALCA is linked to systemic inflammatory response syndrome.