01 Set Proposal for a New Score-Based Approach To Improve Efficiency of Diagnostic Laboratory Workflow for Acute Bacterial Meningitis in Adults

Filippo Lagi

Microbiological tests on cerebrospinal fluid (CSF) follow a common urgent-care procedure that does not take into account the chemical and cytological characteristics of the CSF, resulting sometimes in an unnecessary use of human and diagnostic resources. The aim of this study was to retrospectively validate a simple scoring system (Bacterial Meningitis-Careggi Score; BM-CASCO) based on blood and CSF chemical/cytological parameters for evaluating the probability of acute bacterial meningitis (ABM) in adults. BM-CASCO (range 0-6) was defined by the following parameters: CSF cell count, CSF protein, CSF lactate, CSF glucose/serum glucose ratio and peripheral neutrophil count. BM-CASCO was retrospectively calculated for 784 cases of suspected ABM in adult subjects observed during a four-and-a-half-year-period (2010-2014) at the emergency department (ED) of a large tertiary-care teaching hospital in Italy. Among the 28 confirmed ABM cases (3.5%), Streptococcus pneumoniae was the most frequent cause (16 cases). All ABM cases showed a BM-CASCO value ≥3. Most negative cases (591/756) exhibited a BM-CASCO value ≤1, which was adopted in our laboratory as a cut-off to not proceed with urgent microbiological analysis of CSF in cases of suspect ABM cases in adults. During a subsequent one-year follow-up, the introduction of the BM-CASCO in the diagnostic workflow of ABM in adults resulted in a significant decrease of unnecessary microbiological analysis, with no false negatives. In conclusion, BM-CASCO appears to be an accurate and simple scoring system for optimization of the microbiological diagnostic workflow of ABM in adults.