Cerebrospinal fluid lactate: Is it a reliable and valid marker to distinguish between acute bacterial meningitis and aseptic meningitis?

Cerebrospinal fluid (CSF) lactate assay has been a subject of research since 1925. A systematic review by Huy and colleagues in the previous issue of Critical Care summarizes data from 25 studies evaluating the role of CSF lactate in the differential diagnosis between acute bacterial and aseptic meningitis. The authors concluded that CSF lactate is a good single indicator and a better marker compared with conventional markers. But concerns remain because of poor quality of included studies, lack of proper 'gold standard', and limited applicability. More studies with a rigorous design are needed to determine definitively whether CSF lactate assay is a reliable and valid marker to distinguish between acute bacterial meningitis and aseptic meningitis.