Plasma-Calprotectin as an Indicator for Immediate Need of Intensive Care Treatment in Suspected Sepsis

Abstract Introduction: Decisions regarding need of transfer to intensive care of patients with sepsis in the emergency department is challenging. We hypothesised that the new biomarker plasma-calprotectin could be used to help select patients who need intensive care, since it already has shown to be a promising tool in the intensive care unit. Methods: This prospective study was performed on consecutive sepsis alert patients. The alert summons a multidisciplinary team of physicians from the emergency department, the Department of Infectious Diseases, and the intensive care unit, who evaluate patients for possible infection and decide where to transfer the patient. Blood sampling was performed on consecutive sepsis alert patients. C-reactive protein, procalcitonin, neutrophils, and lymphocytes were routinely analysed, p-calprotectin was analysed from frozen plasma samples using a specific turbidimetric assay. Results: Among 367 sepsis alert patients, 335 had an infection of whom 66 were immediately transferred to the intensive care unit or high dependency unit. 269 patients were transferred to ordinary wards. Median p-calprotectin for all infected patients was 2.2 (IQR 1.2–3.9), 3.3 (IQR 1.6–5.2) among those transferred immediately to intensive care unit/ high dependency unit and 2.1 (IQR 1.1–3.5) among those transferred to wards (p = 0.0001). Analysis of area under the receiver-operating characteristic (ROC) curve for transferral to higher care level showed superiority for p-calprotectin compared to procalcitonin and neutrophil-lymphocyte-ratio, both regarding all sepsis alert cases and regarding the patients with infection (p < 0.001 for all comparisons)). The best p-calprotectin cut-off 4.0 mg/L showed sensitivity 42.5% and specificity 83% for transferral to ICU/HDU among patients with infection. Conclusion: In sepsis alert patients, p-calprotectin was significantly elevated in patients transferred immediately to intensive care. P-calprotectin was superior to traditional biomarkers as a predictor of need for intensive care. Trial registration: Not registered, as the sepsis alert was developed as a clinical supportive tool.