Predictive value of serum and cerebrospinal fluid procalcitonin levels forthe diagnosis of bacterial meningitis

Background: The value of serum and cerebrospinal fluid (CSF) procalcitonin for differentiating between acute bacterial and viral meningitis was assess ed and compared to other parameters which are usually used in clinical prac tice. Patients: 45 adult patients (20 with bacterial and 25 with tick-borne encep halitis, TBE) were included in this prospective study. Results: The median serum procalcitonin level in patients with bacterial me ningitis was 6.45 ng/ml (range 0.25-43.76 ng/ml) and in the group with vira l meningitis 0.27 ng/ml (range 0.05-0.44 ng/ml). 11 patients with bacterial meningitis had an elevated procalcitonin concentration not only in serum, but also in CSF. A serum procalcitonin level > 0.5 ng/ml had a positive pre dictive value for bacterial meningitis of 100% and a negative predictive va lue of 93%, while corresponding values for CSF procalcitonin were 100% and 74%, respectively. Conclusion: Serum and CSF procalcitonin concentrations > 0.5 ng/ml appear t o be a reliable indicator of bacterial central nervous system (CNS) infecti on, with maximal positive predictive values and high negative predictive va lues.