RESUMEN
OBJECTIVE: To define age-specific reference values for cerebrospinal fluid (CSF) total protein levels for children and validate these values in children with Guillain-Barré syndrome (GBS), acute disseminated encephalomyelitis (ADEM) and multiple sclerosis (MS). METHODS: Reference values for CSF total protein levels were determined in an extensive cohort of diagnostic samples from children (<18 year) evaluated at Erasmus Medical Center/Sophia Children's Hospital. These reference values were confirmed in children diagnosed with disorders unrelated to raised CSF total protein level and validated in children with GBS, ADEM and MS. RESULTS: The test results of 6145 diagnostic CSF samples from 3623 children were used to define reference values. The reference values based on the upper limit of the 95% CI (i.e. upper limit of normal) were for 6 months-2 years 0.25 g/L, 2-6 years 0.25 g/L, 6-12 years 0.28 g/L, 12-18 years 0.34 g/L. These reference values were confirmed in a subgroup of 378 children diagnosed with disorders that are not typically associated with increased CSF total protein. In addition, the CSF total protein levels in these children in the first 6 months after birth were highly variable (median 0.47 g/L, IQR 0.26-0.65). According to these new reference values, CSF total protein level was elevated in 85% of children with GBS, 66% with ADEM and 23% with MS. CONCLUSION: More accurate age-specific reference values for CSF total protein levels in children were determined. These new reference values are more sensitive than currently used values for diagnosing GBS and ADEM in children.