- 1-3 mL of Cerebrospinal Fluid (CSF) is collected into each sterile plastic tube; typically 4 tubes are collected
- CSF is collected by lumbar puncture ("spinal tap") using sterile technique
Typical use of each tube:
- Tube 1 - For chemistry and serology testing
- Tube 2 - For microbiology
- Tube 3 or 4 - For miscellaneous testing
- Tube 3 or 4 – For cell count
CSF Protein Calculator: 
CSF WBC Calculator:
- Cerebrospinal Fluid (CSF) is a clear fluid formed in the brain that "bathes" the brain and fills the subarachnoid space.
- CSF is in contact with the extracellular fluid of the brain and its composition is reflective of the brain itself.
- CSF mainly helps in regulation of intracranial pressure (ICP), supply of nutrients to the nervous tissues, and removal of waste products.
- CSF protects the brain and the spinal cord from injury.
- Despite CT and MRI, CSF analysis remains a critical diagnostic tool in the evaluation of neurological disorders.
CSF Formation/Circulation
- In an adult, approximately 150 mL of CSF is in circulation at any moment.
- 500-600 mL of CSF is formed and absorbed daily
- CSF is formed by the choroid plexus, primarily in the lateral ventricles (to a smaller degree in the 3rd and 4th ventricles)
- CSF circulates through the interventricular foramina to the third ventricle, through the cerebral aqueduct into the fourth ventricle and finally to the subarachnoid space covering the brain and spinal cord.
- Following circulation through the subarachnoid space, the CSF enters the intracranial sinuses to be resorbed by the arachnoid villi and granulations
Relationship of blood to CSF
- The blood brain barrier is relatively impervious to cellular compounds; however, CSF is an ultra-filtrate of serum and as such is impacted by the composition of serum
- The blood-CSF barrier is not as impervious and smaller molecular compounds such as glucose, albumin and immunoglobulins will find their way into the CSF from serum, via diffusion.
- A blood specimen drawn at a time close to obtaining CSF is useful for comparison
- CSF glucose level is usually 60% of that of blood glucose level
- CSF protein is typically only 20% derived from the brain and 80% from diffusion from serum into subarachnoid circulating CSF
Table of CSF findings with infection
| Type of infection | WBCs/mm3 | WBC Differential | Protein | Glucose Ratio (Serum:CSF) | Lactate | Opening Pressure |
|---|---|---|---|---|---|---|
| Bacterial | >100 (usually  1000) | Neutrophils dominate in most cases. Lymphocytosis in 10% of cases | Elevated | Normal or decreased | Elevated | Elevated |
| Viral |  300 | Lymphocytosis typical; Neutrophils may dominate early in course | Normal or elevated | Normal (may be decreased in mumps or LCM) | Normal | Normal (typically) |
| Fungal or Tubercular | 500 | Lymphocytosis typical | Elevated | Decreased (typically) | Elevated | Variable |
This section covers CSF appearance & opening pressure in addition to providing an overview. Other specialized sections provide detailed information on each component of CSF testing.
- CSF Chemistries
- CSF Cell counts
- CSF Microbiology
- CSF Special studies – Alzheimer's Dementia testing
- CSF Special studies – Chronic inflammatory demyelinating polyneuropathy testing
- CSF Special studies – Creutzfeldt-Jakob disease testing
- CSF Special studies – Guillain Barré testing
- CSF Special studies – Multiple sclerosis testing
- CSF Special studies – Neurolyme testing
- CSF Special studies – Neurosarcoidosis
- CSF Special studies – Tumor marker testing
CSF Protein Calculator:
CSF WBC Calculator:
- CSF is obtained to evaluate for infection, inflammation, malignancy, or bleeding in the central nervous system
- Additional special tests (some are experimental) are increasingly available for the evaluation of certain conditions such as:
- Alzheimer's Dementia
- Chronic inflammatory demyelinating polyneuropathy (CIDP)
- Creutzfeldt-Jakob disease
- Guillain Barré syndrome
- Multiple sclerosis
- Neurolyme
- Neurosarcoid
- Reye's syndrome
- Tumor markers
Information gained from Lumbar Puncture and CSF Analysis includes:
- Opening pressure (pressure in the brain)
- Glucose
- Protein
- Cell counts
- Gram stain
- Culture for bacteria, fungus, virus
- Bacterial antigens
- Fungal stains
- Viral testing
- Syphilis testing
- Lyme testing
- CSF immunoglobulin levels
- CSF angiotensin-converting enzyme (Neurosarcoid)
- Tumor markers
- Alpha-fetoprotein (AFP)
- Beta-glucuronidase
- Carcinoembryonic antigen (CEA)
- Human chorionic gonadotropin (HCG)
- Lysozyme (muramidase)
- Lactate in mitochondrial cytopathies
- Other specialized testing as condition dictates
Table of CSF findings with infection
| Type of infection | WBCs/mm3 | WBC Differential | Protein | Glucose Ratio (Serum:CSF) | Lactate | Opening Pressure |
|---|---|---|---|---|---|---|
| Bacterial | >100 (usually 1000) | Neutrophils dominate in most cases. Lymphocytosis in 10% of cases | Elevated | Normal or decreased | Elevated | Elevated |
| Viral | 300 | Lymphocytosis typical; Neutrophils may dominate early in course | Normal or elevated | Normal (may be decreased in mumps or LCM) | Normal | Normal (typically) |
| Fungal or Tubercular | 500 | Lymphocytosis typical | Elevated | Decreased (typically) | Elevated | Variable |
Contraindications to performing lumbar puncture:
- Infection overlying site of needle insertion
- Coagulation defects (most commonly increased PT)
- Increased intracranial pressure; especially with space occupying lesion present (e.g. tumor, abscess) as herniation of the brain is a theoretic risk
- Degenerative joint disease (relative contraindication)
Related laboratory tests include:
- Blood chemistries (Glucose, Albumin) to compare with CSF chemistries
- Complete blood count
- Blood culture
- Lyme serology
- Syphilis serology (RPR, VDRL)
This section covers CSF appearance & opening pressure in addition to providing an overview. Other specialized sections provide detailed information on each component of CSF testing.
CSF Protein Calculator:
CSF WBC Calculator:
Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.
Appearance
Normal result is Clear/Colorless
Pressure (Normal)
| Pressure (Normal) | mm H20 |
|---|---|
| Adult | 60–200 |
| Adult (Obese) | 60-250 |
| Child >8 yrs | 60-200 |
| Child <8 yrs | 10–100 |
Pressure (Abnormal)
| Pressure (Abnormal) | mm H20 |
|---|---|
| Adults | |
| Intracranial hypotension | <60 |
| Intracranial hypertension | >250 |
Note: Opening pressure is measured before removal of any CSF and with the patient supine and in relaxed (not hyperflexed) position. Hyperflexion, which is standard and usually needed to introduce the lumbar puncture needle, can elevate pressure readings substantially.
This section covers CSF appearance & opening pressure in addition to providing an overview. Other specialized sections provide detailed information on each component of CSF testing.
CSF Protein Calculator:
CSF WBC Calculator:
Conditions of abnormal CSF appearance include:
- Brown color
- Hyperbilirubinemia (Bili>15 mg/dL)
- Meningeal melanomatosis
- Cloudy/Turbid
- WBC's>200/mm3 in CSF
- RBC's>400/mm3 in CSF
- Green color
- Hyperbilirubinemia (Bili>15 mg/dL)
- Purulent CSF (Meningitis)
- Orange color
- Carotenoid ingestion
- Xanthochromia from blood in CSF that has had time for some breakdown to occur
- Pink/Red color
- Blood in CSF (Intracranial hemorrhage)
- Traumatic lumbar puncture (RBC's introduced due to procedure)
- Yellow color
- CSF protein elevated (>100 mg/dL)
- Hyperbilirubinemia (Bili>15 mg/dL)
- Purulent CSF (Meningitis)
- RBC's in CSF (>100,000/mm3)
- Toxoplasmosis
- Tumor of brain or spinal cord
- Xanthochromia from blood in CSF that has had time for some breakdown to occur
- Is common in newborns (due to increased CSF protein and bilirubin being common)
- 1° Amebic meningoencephalitis typically has CSF that is bloody, purulent, may be turbid
- Tuberculous meningitis typically has CSF that is opalescent, slightly yellow, with delicate clot
- Acute anterior poliomyelitis has CSF that is slightly yellow, may be clear or opalescent, with delicate clot
- Viscous CSF
- Metastatic cancer to CNS
- Severe meningeal infection
- Cryptococcus
- CNS injury
Conditions where CSF pressure is increased (>250 mm H20 in an adult) is defined as intracranial hypertension. Conditions that cause this include:
- Cerebral edema
- Conditions inhibiting CSF absorption
- Congestive heart failure
- Hypo-osmolality as a result of hemodialysis
- Intracranial mass occupying lesions
- Abscess
- Intracranial hemorrhage
- Subdural bleed
- Tumor
- Other lesions
- Meningitis
- Bacterial
- Fungal
- Viral
- Syphilitic
- Subarachnoid hemorrhage
- Subdural hemorrhage
- Superior vena cava syndrome
- Thrombosis of venous sinuses
This section covers CSF appearance & opening pressure in addition to providing an overview. Other specialized sections provide detailed information on each component of CSF testing.
CSF Protein Calculator:
CSF WBC Calculator:
Conditions where CSF pressure is decreased, includes:
- Circulatory collapse
- CSF leak (prior lumbar puncture, trauma with CSF leak)
- Dehydration (severe)
- Hyperosmolality
- Spinal-subarachnoid block
This section covers CSF appearance & opening pressure in addition to providing an overview. Other specialized sections provide detailed information on each component of CSF testing.
- Bera S et al. Detection of antigen and antibody in childhood tuberculous meningitis. Indian J Pediatr. 2006 Aug; 73(8):675-9
- Chavanet P et al. Performance of a predictive rule to distinguish bacterial and viral meningitis. J Infect. 2006 Aug 1; [Epub ahead of print]
- Freedman MS et al. Recommended standard of cerebrospinal fluid analysis in the diagnosis of multiple sclerosis: a consensus statement. Arch Neurol. 2005 Jun;62(6):867-70
- Griffiths PD et al. Malformations of the fetal spine using in utero MR imaging. Cerebrospinal Fluid Research 2005, 2(Suppl 1): S18 doi: 10.1186/1743-8454-2-S1-S18
- Jakka SR et al. Characteristic abnormalities in cerebrospinal fluid biochemistry in children with cerebral malaria compared to viral encephalitis. Cerebrospinal Fluid Research 2006, 3:8 doi: 10.1186/1743-8454-3-8
- Kawashima H et al. Primary biomarkers in cerebral spinal fluid obtained from patients with influenza-associated encephalopathy analyzed by metabolomics. Int j Neurosci. 2006 Aug; 116(8): 927-36
- Narkeviciucte I et al. Aetiological diagnostics of acute bacterial meningitis in children. Scand J Infect Dis. 2006; 38(9): 782-7
- Rikonen R et al. Cerebrospinal fluid insulin-like growth factors IGF-1 and IGF-2 in infantile autism. Dev Med Child Neurol. 2006 Sep; 48(9): 751-5
- Seehusen DA et al. Cerebrospinal Fluid Analysis. Am Fam Phy. 2003;68:1103-8.
- Silverberg G et al. Elevated cerebrospinal fluid pressure in patients with Alzheimer's disease. Cerebrospinal Fluid Research 2006, 3:7 doi: 10.1186/1743-8454-3-7