Background: Severe sepsis, septic shock and bacteremia are critical illnesses, and patients with these conditions require close monitoring and immediate medical treatment. Any delay in diagnosis may lead to an increase in mortality in such critically ill patients. Serum procalcitonin (PCT) has emerged as a highly accurate biomarker for differentiating sepsis from other non-infectious triggers.
Objective: In this study, we investigated the effectiveness of PCT in obtaining early diagnosis and efficient prognosis for such
patients at the Emergency Department of Rajavithi Hospital.
Material and Method: A prospective study was performed of 110 adult patients who attended the emergency service
department between August 1 2013 and October 31 2013. The effectiveness of PCT as a specific blood test analysis tool for
detecting and classifying the severity of patients with sepsis was investigated, and sensitivity, specificity, negative predictive values (NPV), positive predictive values (PPV) and positive likelihood ratio (LR+) were used to differentiate infected patients.
Results: One hundred and ten patients were enrolled and classified into 3 categories as follows: severe sepsis (n = 34,
30.9%), septic shock (n = 13, 11.8%), and bacteremia (n = 23, 20.9%). At a PCT level of >2 ng/dL, it was feasible to
categorize patients as having severe sepsis (p<0.001; RR 3.58; 95% CI 2.18-5.89), septic shock (p = 0.001; 5.73; 2.06-
15.93) or bacteremia (p<0.001; 3.91; 1.98-7.73). Moreover, the PCT value yielded the following diagnostic performances for
patients with: severe sepsis (PPV 70.8%; NPV 80.2%; LR+ 5.0; sensitivity 50.0%; specificity 90.8%); septic shock (33.3%; 94.2%; 3.6; 61.5%; 83.5%); and bacteremia (50.0%; 87.2%; 3.7; 52.2%; 86.2%).
Conclusion: PCT can be usefully employed as a promising chemical biomarker to differentiate the severity of infections in
critically ill patients. Used together with clinical data, the PCT value of >2 ng/dL is efficient in categorizing such patients as
having severe sepsis, septic shock or bacteremia.

Keywords: Procalcitonin, Severe sepsis, Septic shock, Bacteremia, Emergency department