Erythropoietin in cerebrospinal fluid: age-related reference values and relevance in neurological disease.

We aimed to establish age-related reference values for Erythropoietin (EPO) in cerebrospinal fluid (CSF) and to evaluate concentrations in neurological diseases. CSF and serum EPO was measured in controls with tension-type headache (CTTH), in patients with ALS, dementia and depression using ELISA technique. Stability experiments showed CSF EPO to be stable for two and a half months and over two thaw/freeze cycles. A positive correlation of CSF EPO with age was found (P<0.01). We found a CSF/serum EPO concentration ratio of 0.126, pointing towards an intrathecal synthesis of EPO. The ALS group showed significantly lowered CSF EPO compared to age-matched CTTH (P<0.012), whereas the dementia and depression group showed no significant differences compared to CTTH.The establishment of age-related reference values in a large cohort of controls will improve the interpretation of future CSF EPO evaluations in neurological diseases.