Serum Procalcitonin as a Diagnostic Marker for Systemic Inflammatory Response Syndrome in Intensive Care Unit Patients

Introduction: Early assessment of Systemic Inflammatory Response Syndrome (SIRS) through various biomarkers like Procalcitonin (PCT), C-reactive Protein (CRP), Interleukin-1 (IL-1) etc., is crucial to manage the outcome of patients. Levels of PCT concerning its likelihood to distinguish patients with SIRS and non-SIRS and the possibility to predict mortality in patients with sepsis has been variable. Aim: To investigate the role of PCT in early diagnosis of sepsis in patients admitted to Intensive Care Unit (ICU). Materials and Methods: In this prospective observational study, 136 patients hospitalised in ICU at Vydehi Institute of Medical Sciences and Research Centre, Bangalore, Karnataka, India, between July 2019 to June 2020 were evaluated and PCT was analysed using Finecare™ PCT rapid test. Receiver Operating Characteristic (ROC) curve analysis and multiple logistic regression was carried out to detect the association of predictive PCT value with its outcomes. Results: PCT showed the best predictive value in the diagnosis of SIRS at 1.68 ng/mL (Area Under Curve (AUC)-0.87; p<0.05) having Positive Predictive Value (PPV) and Negative Predictive Value (NPV) of 90.43% and 73.81%, respectively. Multiple logistic regression model adjusted for age, weight, and duration of stay to predict the outcome of SIRS, positive blood culture and fatality case rate derived a significant association of PCT with Odds Ratio (OR) being 1.23 (1.11-2.31), 1.06 (1.01-1.98) and 1.76 (1.08-2.14), respectively. Conclusion: Early identification and treatment for sepsis significantly affects mortality. It appears that consecutive measurements of biomarkers could be valuable, but further prospective studies are important to characterise the role of PCT as a prognostic marker in sepsis and severe sepsis.