Cerebrospinal Fluid Analysis – Part 1 – Cerebrospinal Fluid Normal Findings(CSF)
Definition of the cerebrospinal fluid (CSF)
- This is a clear, colorless, fluid similar to blood plasma and interstitial fluid.
- Approximately 600 mL of the CSF is produced daily.
- Around 125 to 150 mL of CSF circulates in the ventricles and subarachnoid space.
- Choroid plexus in the lateral, third, and fourth ventricles produce a major portion of the CSF.
- CSF does not accumulate but it is reabsorbed into venous circulation through arachnoid villi.
- CSF is formed by the blood and after circulating throughout the CNS, it returns to the blood.
Function of CSF
- The intracranial and the spinal cord float in the CSF and are therefore protected from the blows and the jolts.
- The buoyant properties of the CSF prevent the brain from tugging on meninges. nerve roots, and blood vessels.
- Its main function is to protect the brain and spinal cord from the injury.
- It transports the substances through the central nervous system.
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Appearance
- it is clear and colorless.
- This clear protein circulates in the subarachnoid space.
- No clot is seen.
- it is clear and colorless.
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Pressure
- It is 70 to 180 mm of H2O or 5 to 14 mm of Hg.
- This pressure is when the person is lying down and it doubles up when the person sits up.
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Total cell count
- In adult is 0 to 5 / cmm .
- These are mononuclear cells.
- In infants are 0 to 20 / cmm.
- No RBC is seen.
- In adult is 0 to 5 / cmm .
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Glucose
- It is 45 to 80 mg /dL .
- This is 20 mg /dL lower than the blood glucose level.
- Ventricular glucose is 5 to 10 mg higher than the lumbar CSF.
- It is 45 to 80 mg /dL .
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Protein
- It is 15 to 45 mg / dL in lumbar CSF.
- It is 15 to 25 mg / dL in the cisternal fluid.
- It is 5 to 15 mg / dL in the ventricular fluid.
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Gamma globulin
- It is 3 to 12 % of the total protein.
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Chloride
- It is from 120 to 130 meq / L.
- It is 20 meq higher than the serum.
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LDH
- It is 15 to 17 units/L
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Bilirubin
- It is negative.
Table showing Normal CSF findings:
Lab findings | Source 2 | Source 1 | Source 4 |
Volume |
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Pressure | <20 cm H2O | 50 to 180 mm H2O (If the pressure >180 mm H2O, then do not take more than 1 to 2 ml of CSF) |
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Appearance | Clear and colorless, no clot | Crystal clear, and colorless | Clear and colorless |
Blood | Nil | Negative | Nil |
White cell count | Neonates = 0 to 30 cell/µL | 0 to 30 cells |
|
1 to 5 years = 0 to 20 cells/ µL | |||
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0 to 5 cells | ||
Differential count | |||
Neutrophils | 0 to 6% |
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Lymphocytes | 40 to 80% |
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Monocytes | 15 to 45% |
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Protein |
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Lumbar area |
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Adult = 15 to 45 mg/dL | |
Cisternal area | 15 to 25 mg/dL | Adult = 15 to 45 mg/dL = lumbar | |
Ventricular area | 5 to 15 mg/dL | Adult = 5 to 15 mg/dL | |
Electrophoresis
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Prealbumin | 2 to 7% | 2 to 7% | |
Albumin | 56 to 76% | 10 to 35 mg/dL | 56 to 76% |
Alpha1 globulin | 2 to 7% | 2 to 7% | |
Alpha2 globulin | 4 to 12% | 4 to 12% | |
Beta globulin | 8 to 18% | 8 to 18% | |
Gamma globulin | 3 to 12% | 3 to 12% | |
IgG | 0 to 4.5 mg/dL | <4.0 mg/dL | |
Oligoclonal band | Negative | Negative | |
Biochemical estimation
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Glucose | 50 to 75 mg/dL (60 to 70% of blood glucose) |
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pH |
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Sodium | 135 to 160 meq/L | ||
Potassium | 2.6 to 3.0 meq/L | ||
Chloride | 700 to 750 mg/dL | 115 to 130 meq/L |
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LDH | <2 to 7.2 units/mL | <20 U/L | Adult = <20 U/L (around 10% of serum) |
Lactic acid | 10 to 25 mg/dL | 10 to 24 mg/dL |
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Glutamine | 6 to 15 mg/dL |
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Urea nitrogen | 6 to 16 mg/dL | ||
Phosphorus | 1.2 to 2.0 mg/dL | ||
Creatinine | 0.5 to 1.2 mg/dL | ||
Uric acid | 0.5 to 4.5 mg/dL | ||
Bilirubin | Negative | ||
ammonia | 10 to 35 µg/dL | ||
Syphilis serology | Negative | Negative | Negative |
CSF cytology for malignancy | Negative | Negative | Negative |