Procalcitonin May Not Discriminate Between Sepsis and Non-Infective Systemic Inflammatory Response Syndrome (SIRS) in Heterogonous Critically Ill Patients

[Background]In recent decades Procalcitonin (PCT) has been introduced to help physicians differentiate sepsis from SIRS. Its routine use in such specific settings as ICU, on the other hand, is very polemical owing to the variable results.[Objectives]In this prospective observational study, we examined the accuracy of PCT levels in differentiating septic from SIRS in critically ill patients admitted to the general ICUs of two hospitals in Tabriz, Iran from September 2014 to May 2016. Further appraised was the effect of illness severity and organ failure on PCT value. We tried to answer this question that why there is controversial and wide range of findings pertaining to PCT in critical care settings.[Methods]One hundred and thirty two SIRS (Systemic Inflammatory Response Syndrome) positive critically ill patients admitted to the ICU were enrolled in the present research. Patients were divided based on their positive cultures into infectious and SIRS positive groups, in both of which, PCT was measured, severity of illness and organ failure were recorded, and the PCT sensitivity and specificity for the detection of sepsis and its relationship with disease severity and mortality were evaluated.[Results]The optimal cut-off point for the PCT, determined 0.25μg/L with a sensitivity and specificity of 73 % and 39 %, respectively. PCT level was not able to significantly diagnose septic patients from SIRS positive ones and was significantly correlated with Cr and BUN concentrations.[Conclusions]These findings indicate that PCT may not differentiate between sepsis and SIRS in a heterogeneous population of critically ill patients admitted to the ICU; PCT measurements, nonetheless, can probably conduce to predicting the outcome of patients.