Differential diagnostic value of procalcitonin in surgical and medical patients with septic shock

Objective: To assess whether different diagnostic and prognostic cutoff values of procalcitonin should be considered in surgical and in medical patients with septic shock. Design: Prospective observational study. Setting: Intensive care unit of the Avicenne teaching hospital, France. Patients: All patients with septic shock or noninfectious systemic inflammatory response syndrome within 48 hrs after admission. Interventions: None. Measurements and Main Results: Patients were allocated to one of the following groups: group 1 (surgical patients with septic shock), group 2 (surgical patients with noninfectious systemic inflammatory response syndrome), group 3 (medical patients with septic shock), and group 4 (medical patients with noninfectious systemic inflammatory response syndrome). Procalcitonin at study entry was compared between group 1 and group 2 and between group 3 and group 4 to determine the diagnostic cutoff value in surgical and in medical patients, respectively. Procalcitonin was compared between survivors and nonsurvivors group 1 and group 3 to determine its prognostic cutoff value. One hundred forty-three patients were included: 31 in group 1, 36 in group 2, 36 in group 3, and 40 in group 4. Median procalcitonin levels (ng/mL [interquartile range]) were higher in group 1 than in group 3 (34.00 [7.10-76.00] vs. 8.40 [3.63-24.70], p =.01). In surgical patients, the best diagnostic cutoff value was 9.70 ng/ mL, with 91.7% sensitivity and 74.2% specificity. In medical patients, the best diagnostic cutoff value was 1.00 ng/mL, with 80% sensitivity and 94% specificity. Procalcitonin was a reliable early prognostic marker in medical but not in surgical patients with septic shock. A cutoff value of 6.00 ng/mL had 76% sensitivity and 72.7% specificity for separating survivors from nonsurvivors. Conclusions: The diagnostic cutoff value of procalcitonin was higher in surgical than in medical patients. Early procalcitonin was of prognostic interest in medical patients.