CSF opening pressure: 50–180 mmH2O Glucose: 40–85 mg/dL. Protein (total): 15–45 mg/dL. Lactate dehyrogenase: 1/10 of serum level. Lactate: less than 35 mg/dL. Leukocytes (WBC): 0–5/µL (adults / children); up to 30/µL (newborns). Gram stain: negative. Culture: sterile. Specific gravity: 1.006–1.009. Syphilis serology: negative. Gross appearance: Normal CSF is clear and colorless. Differential: 60–70% lymphocytes; up to 30% monocytes
and macrophages; other cells 2% or less.