Physical characteristics

The appearance of the sample of CSF is usually compared to a sample of water.
  • Pressure of the CSF can be measured when opening (starting) and closing (finishing) the collection.
    • Increased CSF pressure may be seen with a variety of conditions that increase pressure within the brain or skull and/or that obstruct the flow of CSF, such as tumours, infection, abnormal accumulation of CSF within the brain (hydrocephalus), or bleeding.
    • Decreased pressure may be due to dehydration, shock, or leakage of CSF through an opening (another lumbar puncture site or sinus fracture).
  • Colour of the fluid - normal is clear and colourless. Changes in the colour of the CSF are not diagnostic but may point to additional substances in the fluid. Yellow, orange or pink CSF is said to be xanthochromic. It may indicate the breakdown of blood cells due to bleeding into the CSF or the presence of bilirubin. Green CSF may also sometimes be seen with bilirubin or infection.
  • Turbidity - Cloudy or turbid CSF may indicate the presence of white or red blood cells, microorganisms or an increase in protein levels.
  • Viscosity - Normal CSF will have the same consistency as water. CSF that is “thicker” may be seen in patients with certain types of cancers or meningitis.

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