Evaluation of Serum Procalcitonin in Patients with Systemic Inflammatory Response Syndrome with and without Infection

Abstract- Procalcitonin (PCT) is a precursor peptide for the hormone calcitonin and is frequently increased in overt sepsis. The aim of this study was to test diagnostic accuracy of procalcitonin among patients with positive systemic inflammatory response syndrome (SIRS) in identifying sepsis. In this cross sectional study, from 563 patients with positive SIRS admitted through the emergency department of a university hospital, we included 120 patients. Procalcitonin was measured semi-quantitatively. Two groups of patients (with and without infection) were defined based on clinical, laboratory and bacteriologic findings throughout the admis-sion course; the serum PCT levels were compared between the two groups. Seventy two (60%) patients were male and 48 (40%) were female, and the mean age was 49.1 ± 20.2 years. Final diagnosis was infection in 71 patients (59.2%) and 49 (40.8%) had non-infectious SIRS. When considering PCT> 0.5 µg/L as the cut-off point, PCT had a sensitivity of 88.7%, a specificity of 77.6%, a positive predictive value of 85.1 % and a negative predictive value of 82.6%. Serum level of procalcitonin in infectious group was significantly higher than in non-infectious group (P < 0.0001). PCT level was a predictor of mortality in patients with infectious SIRS. (P = 0.01) In summary, PCT is a useful marker for differentiating sepsis from other cause of SIRS. With change in the cut-off value of PCT in any situation its application can be maximized. Procalcitonin can