Serum levels of procalcitonin as a biomarker for differentiating between sepsis and systemic inflammatory response syndrome in the neurological intensive care unit.

We explored the value of procalcitonin (PCT) to differentiate sepsis from systemic inflammatory response syndrome (SIRS), and determine sepsis severity in the neurological intensive care unit (NICU). Blood samples were measured for C-reactive protein (CRP) and PCT levels upon NICU admission, on the day of diagnosis of SIRS or sepsis, and at 3 and 7 days after diagnosis. We found that there were significant differences in serum levels of CRP and PCT as well as Glasgow Coma Scale (GCS) score upon admission between the SIRS and sepsis groups (p<0.05). CRP and white blood cell levels were not significantly different when attempting to differentiate sepsis severity (p>0.05). Multiple comparisons showed that significant differences in serum PCT levels were observed between sepsis and severe sepsis groups, as well as sepsis and septic shock groups (p<0.05). We obtained the highest sensitivity and specificity for SIRS and sepsis with cut-off values of 2 ng/mL for PCT, 44 mg/dL for CRP, and 4 for the GCS. There were no differences in CRP and PCT levels between cerebrovascular disease and non-cerebrovascular disease groups (p>0.05). No differences were found between viral and bacterial meningitis groups (p>0.05). PCT levels are valuable in discriminating sepsis from SIRS and determining sepsis severity in critically ill patients with neurological disease.