Normal
Subarachnoid Haemorrhage
Traumatic Tap
Opening Pressure (cm/H2O)
5-20
May be Elevated (60% of cases)
Normal
Appearance
Clear
Grossly bloody to clear
Grossly bloody or clear
RBC (per mm3)
<5
Elevated
(usually uniform in all tubes)
(usually uniform in all tubes)
Elevated
(typically varies from tube to tube, being greatest in Tube #1)
(typically varies from tube to tube, being greatest in Tube #1)
WCC (per mm3)
<3
Elevated
(can corrected eby subtracting 1 per 1000 RBCs)
(can corrected eby subtracting 1 per 1000 RBCs)
Elevated
(can corrected by subtracting 1 per 1000 RBCs)
(can corrected by subtracting 1 per 1000 RBCs)
Protein (g/L)
0.2-0.4
Elevated
(can corrected by subtracting 10mg/L for every 1000 RBCs/mm3)
(can corrected by subtracting 10mg/L for every 1000 RBCs/mm3)
Elevated
(can corrected by subtracting 10mg/L for every 1000 RBCs/mm3)
(can corrected by subtracting 10mg/L for every 1000 RBCs/mm3)
Glucose-Serum Ratio
0.5-0.66
(2.5-3.5 mmol/L)
(2.5-3.5 mmol/L)
Normal
Normal
Xanthochromia
-
Typically present if duration over 2-12 hours
Absent
(unless CSF protein >150 mg/dl or severe jaundice)
(unless CSF protein >150 mg/dl or severe jaundice)