the CSF collected using a bright white light source for general
appearance. It is best to hold the second tube against a white paper
background so as to detect any subtle color changes. Normal CSF
should be crystal clear and colourless.
Examine the CSF fluid for a blood-tinged appearance. Blood may be
present for a number of reasons, including SAH. A "traumatic
tap" occurs if the needle inadvertently has entered an
epidural vein during insertion.
yellowish tinge to the CSF fluid is called xanthochromia.
Xanthochromia is usually caused by red blood cell degeneration
the CSF as would be seen in subarachnoid hemorrhage (SAH). The
breakdown of red blood cells takes many hours to occur. Xanthochromia
would be reliably seen by 12 hours and can persist for up to
2 weeks [this assumes that Vermulen1 was correct. His paper
is a case series of patients with known SAH, not undifferentiated
headache patients. The detection of xanthochromia in this study
employed spectrophotometry.] Other causes of xanthochromia include
systemic jaundice and
causing elevated CSF protein.
M, Hasan D, Blijenberg BG, Hijdra A, van Gijn J. Xanthochromia
after subarachnoid haemorrhage needs
no revisitation. J Neurology, Neurosurgery and Psychiatry 1989;
It has been reported that detecting and quantifying xanthochromia
may be more accurate using a spectrophotometer. Currently the availability
of this testing method is limited in North America. The overall
sensitivity and specificity of the technique are not currently
known in the patient with an undifferentiated headache.
a standard laboratory reference to interpret the results of the
CSF fluid analysis. Emergency physicians may need to seek consultation
with an appropriate specialty service.
following are general principles:
In subarachnoid hemorrhage:
<10 X 10 6/L *Presence of more than a few RBCs may indicate
cerebral or subarachnoid hemorrhage or traumatic tap.
may be present (see above in this section).Red cells are present
after SAH and may be present after trauma, or with haemorrhagic
inflammation (e.g. HSV encephalitis from Herpes Simplex Virus).
If there is blood, determine if there is more blood in tube
1 than in tube 4. Typically RBC counts are comparatively higher
in tube 1 than in tube 4 in a traumatic tap and roughly equal
Information Handbook 2002, The Ottawa Hospital
Turbidity or cloudiness can be seen when the white blood cell count
(WBC) of the CSF is elevated. A high WBC indicates that there is
inflammation of the central nervous system, as in meningitis for
0-10 X 10 6/L*
0-30 X10 6/L*
mmol/L (~0.6 _ serum conc)*
0.12-0.60 g/L Conversion factor:
mg/L X 0.001 = g/L*
lymphocytes neutophils may be seen early
traumatic tap may result in blood in the CSF. There should
only be 1 white cell to every 700 red cells. A higher ratio
indicates the possibility of meningitis. A brief course
(less than 2 days) of antibiotic therapy is unlikely to
affect the CSF cell count, protein or glucose levels but
does reduce the probability of seeing bacteria with a Gram
stain or of isolating an organism from cultures.In TB or
fungal meningitis, mostly lymphocytes or monocytes are seen.
CSF glucose levels, as compared to plasma levels, are seen
in bacterial meningitis, cryptococcal meningitis, malignant
involvement of the meninges and sarcoidosis. High CSF protein
levels are seen:
conditions in which there is pus or blood in the CSF,
meningeal inflammation (e.g. purulent or tuberculous meningitis),with
increased blood-brain vascular permeability (e.g. encephalitis,
local immunoglobulin production (e.g. multiple sclerosis),
CSF circulation is impeded (e.g. spinal tumour).
Handbook, The Ottawa Hospital
Web link for
analysis of CSF from The Royal College of Pathologists of Australasia