Cerebrospinal fluid protein: what is a normal reference range?

Cody et al. provide evidence that cerebrospinal fluid (CSF) analysis can provide invaluable diagnostic information. This study identified a CSF protein level > 0.45 g/L in 21.5% of cases. A commonly endorsed reference range for CSF protein is 0.15–0.45 g/L.2However, it is important to examine the evidence behind institutional reference ranges to prevent false positives and false negatives. This consideration is especially important in the context of neurological emergencies, in which inaccurate results may lead to inappropriate treatment or the withholding of such.