cerebrospinal fluid analysis

Introduction

Routine CSF analysis:

• Cell count* with differential*
• Gram stain
• Bacterial cultures
• CSF glucose & serum glucose
• CSF protein#
• CSF VDRL
• CSF xanthochromia (presence)

* 0-5 cells/uL (0 to 14-30 cells/uL neonates)

lymphocytes 62% +/- 34%

monocytes 36% +/- 20%

neutrophils 2% +/- 5%

# CSF protein concentration increases as it passes from the ventricles to lumbar spine

ventricular CSF 5-15 mg/dL (total protein)

cisternal CSF 15-25 mg/dL

lumbar CSF 15-45 mg/dL

Other CSF analyses depending upon clinical presentation

• mycobacterial & fungal stains
• mycobacterial cultures
• serology for coccidioidomycosis
• bacterial, viral, fungal antigens
• multiple sclerosis panel
  • need serum & CSF
  • serum & CSF protein electrophoresis
  • antibody to myelin basic protein
• cytology
• tumor markers
  • paraneoplastic antibody in CSF

Tube # 1: protein, glucose

Tube # 2: gram stain

Tube # 3: cell count

Tube # 4: saved for special studies

CSF pressure: 10-15 cm H2O

CSF appearance: clear, colorless

CSF glucose: 40-70 mg/dL (60-70% of peripheral blood glucose)

CSF protein 15-45 mg/dL

CSF cell count: < 5 mononuclear leukocytes/mm3

CSF pressure:

• increased in bacterial, tuberculis or fungal meningitis
• may be increased or normal in viral meningitis
• increased in subarachnoid hemorrhage
• increased in meningeal carcinomatosis
• increased in Pseudotumor cerebri
• normal or increased in Guillain Barre syndrome
• normal in multiple sclerosis

CSF appearance:

• cloudy in bacterial meningitis
• clear, maybe cloudy in tuberculis or fungal meningitis
• clear in viral meningitis
• clear in meningeal carcinomatosis
• bloody with xanthochromic supernatant in subarachnoid hemorrhage
• bloody with clear supernatant in traumatic tap
  • RBC count <2000 106/L & no xanthochromia distinguishes traumatic tap from subarachnoid hemorrhage
• clear in multiple sclerosis
• clear or xanthochromic in Guillain Barre syndrome
• clear in pseudotumor cerebri

CSF glucose:

• decreased in bacterial meningitis, tuberculous meningitis
  • may be normal with listeriosis
• normal or decreased in tuberculous or fungal meningitis
• normal in viral meningitis
• normal or decreased in meningeal carcinomatosis
• normal in paraneoplastic limbic encephalitis
• normal in subarachnoid hemorrhage
• normal in multiple sclerosis or Guillain Barre
• normal in pseudotumor cerebri

CSF protein:

• increased in bacterial, tuberculous & fungal meningitis
• normal or increased in viral meningitis
• normal or increased in meningeal carcinomatosis
• increased in subarachnoid hemorrhage
• increased in traumatic tap
• normal or increased in multiple sclerosis
• very increased in Guillain Barre syndrome
• normal in pseudotumor cerebri

CSF cell count:

• 500-10,000/mm3 with predominance of neutrophils in bacterial meningitis
  • listeriosis may present with either neutrophil or lymphocyte predominance with cell counts of 10-500/mm3
• 10-500/mm3 with predominance of lymphocytes in tuberculous or fungal meningitis
• > 6 lymphocytes/mm3 in viral meningitis
• 10-500/mm3 with predominance of lymphocytes in meningeal carcinomatosis or paraneoplastic limbic encephalitis
• 1000-3,500,000/mm3 RBCs with RBC:WBC ratio higher than peripheral blood in subarachnoid hemorrhage
• fewer RBC in collection tube 4 than collection tube 1 intraumatic tap
• 0-20 lymphocytes/mm3 in multiple sclerosis
• < 5 mononuclear cells/mm3 (normal pattern) in Guillain-Barre & pseudotumor cerebri

Notes

• if CSF leukocytosis & viral markers negative, consider paraneoplastic limbic encephalitis if malignancy identified vs acid fast stain & culture

More general terms

• chemistry panel
• hematology panel
• microbiology panel

More specific terms

• CSF cell count
• CSF volume
• hemoglobin in CSF

Additional terms

• reference values for CSF constituents

Components

• CSF cell count
• CSF gram stain
• bacterial culture
• glucose in CSF
• glucose in serum/plasma
• protein in cerebrospinal fluid (CSF)
• VDRL reagin slide CSF (CSF VDRL)
• CSF Xanthochromia