P lacement of external ventricular drainage (EVD) and draining of the cerebrospinal fluid (CSF) when intracranial pressure (ICP) is elevated are frequently used for treating intracranial hypertension caused by a variety of neurological conditions. However, such an invasive procedure allows free entrance for bacteria and presents an increased risk of infection that can lead to meningitis, ventriculitis, or even death. The incidence of EVD-related ventriculitis ranges from 10% to 27% according to the literature (1-5). The most significant group of microorganisms causing ventriculitis is Staphylococcus spp., especially coagulase-negative staphylococci, followed by Staphylococcus aureus. Other Grampositive organisms, such as Streptococcus spp., Enterococcus spp., Corynebacterium spp., and Propionibacterium spp., may be involved. Most ventricular infections are a result of contamination during the insertion of the EVD (6, 7). In order to prevent this complication or to detect initiating steps of the disease, early diagnosis and treatment are crucial, yet little has been reported in the literature about its management. The CSF total cell count, differential count, and concentration of proteins and glucose are parameters providing early information pertaining to the diagnosis of bacterial CSF infection. However, cell counts are often unreliable because of blood contamination of the CSF caused by primary or secondary ventricular hemorrhage or by chemical reactions to the drain material. Blood laboratory markers are also frequently elevated because of concomitant bacterial infection (8). C-reactive protein (CRP) and procalcitonin (PCT) were tested for their use to predict infection, but the results were contradictory (8, 9). Bacteriological culture methods such as CSF cultures may take several days until bacterial growth can safely be excluded (9). Furthermore, many patients with EVD are on antibiotic therapy and isolation of bacteria from CSF is often difficult. Thus, there is a need for new markers with higher specificity for early detection of meningitis and ventriculitis. Brain macrophages play a pivotal role during inflammatory reactions of the central nervous system (CNS) parenchyma, ventricles, and meninges, and are involved in the release of soluble CD14 (sCD14) (10). In a study of 91 patients, serum sCD14 levels were measured, and the levels increased during acute bacterial meningitis. Increased CSF and serum sCD14 concentrations were also observed in meningitis caused by viral infection. Repeated measurement of sCD14 in CSF revealed a normalization of sCD14 levels during clinical recovery (10). Determination of presepsin (sCD14-ST) in CSF could overcome problems with time-consuming procedures while measuring sCD14. CD14 is a glycosylphosphatidylinositol (GPI)-anchored glycoprotein