Synonym

• CSF chemistries
• Chemistries, CSF
• Glucose, CSF
• CSF Glucose
• Protein, CSF
• CSF Protein
• Lactate, CSF
• CSF Lactate
• Lactic acid, CSF
• CSF lactic acid

Tubes

• 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

Info

CSF Protein Calculator:

Overview of CSF

• 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 3^rd and 4^th 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

This section covers CSF chemistries. Other sections provide detailed information on other components of CSF testing.

• CSF Testing Overview
• CSF Cell counts
• CSF Microbiology

Clinical

CSF Protein Calculator:

• CSF is obtained to evaluate for infection, inflammation, malignancy, or bleeding in the central nervous system
• Additional special tests (mostly experimental) are increasingly available for the evaluation of other conditions such as multiple sclerosis or dementia

Information gained from CSF Chemistries includes:

• Glucose
• Protein
• Lactate

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 chemistries. Other sections provide detailed information on other components of CSF testing.

• CSF Testing Overview
• CSF Cell counts
• CSF Microbiology

Nl Result

CSF Protein Calculator:

Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.

This section covers CSF chemistries. Other sections provide detailed information on other components of CSF testing.

• CSF Testing Overview
• CSF Cell counts
• CSF Microbiology

High Result

CSF Protein Calculator:

Conditions that may increase CSF glucose levels include:

• Diabetes (poorly controlled)
• Hyperglycemia of any cause
• CSF glucose in adults is normally equal to serum glucose x 0.6 (usually never exceeds 300 mg/dL regardless of serum level)

An increase in CSF protein is seen in conditions that include:

• Blood in the CSF
• Traumatic lumbar puncture
• Intracranial hemorrhage
• Increased permeability of blood-CSF barrier (CSF protein 100–500 mg/dL)
• CNS abscess
• Cerebral hemorrhage or thrombosis
• Cerebritis or any other inflammatory condition of the CNS
• Endocrine disorders
• Diabetes
• Myxedema
• Hyperadrenalism
• Hypoparathyroidism
• Guillain Barré syndrome
• Intracerebral hemorrhage
• Meningitis
• Bacterial
• Fungal
• Neurosyphilis
• Tuberculosis
• Viral
• Metabolic disorders
• Dehydration
• Hypercalcemia
• Hypercapnia
• Uremia
• Multiple sclerosis
• Polyneuritis
• Trauma to CNS

Increased CSF lactic acid levels are associated with the following conditions:

• Brain abscess or tumor
• Cerebral trauma
• Meningitis
• Bacterial
• Fungal
• Listeria
• Seizures
• Stroke (cerebral infarct)

Drugs that may increase CSF glucose levels include:

• Cefotaxime
• Dexamethasone

Drugs causing an increase in CSF protein, include:

• Ethanol
• Phenothiazines
• Phenytoin

This section covers CSF chemistries. Other sections provide detailed information on other components of CSF testing.

• CSF Testing Overview
• CSF Cell counts
• CSF Microbiology

Low Result

CSF Protein Calculator:

Conditions where CSF glucose levels are decreased include:

• Hypoglycemia (Systemic)
• Malignant tumor with meningeal involvement
• Meningitis
• Bacterial
• Amebic
• Fungal
• Syphilis
• Tuberculosis
• Nonbacterial meningoencephalitis
• Subarachnoid hemorrhage

^* Note that in viral meningitis, CSF glucose is usually normal and in bacterial meningitis, up to 50% of patients will have normal CSF glucose

Conditions that may decrease CSF protein levels include:

• Acute water intoxication
• Hyperthyroidism
• Intracranial hypertension
• Leakage of CSF due to trauma
• Rapid CSF production
• Removal of a large volumes of CSF or repeated lumbar puncture
• Young children between 6 months and 2 yrs of age

Drugs that may decrease CSF protein levels include:

• Cefotaxime
• Dexamethasone

This section covers CSF chemistries. Other sections provide detailed information on other components of CSF testing.

• CSF Testing Overview
• CSF Cell counts
• CSF Microbiology

References

• Bera S et al. Detection of antigen and antibody in childhood tuberculous meningitis. Indian J Pediatr. 2006 Aug; 73(8):675-9
• Body BA et al. Use of cerebrospinal fluid lactic acid concentration in the diagnosis of fungal meningitis. Annals of Clinical and Laboratory Science. 1987; 17(6):429-434
• 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