neurologic disorders
Lumbar Puncture (Spinal Tap)
CSF color
Normal CSF is clear and colorless;≥300 cells/microL produces cloudiness or turbidity. Bloody fluid may indicate a traumatic puncture (pushing the needle in too far, into the venous plexus along the anterior spinal canal) or Subarachnoid Hemorrhage (SAH) . A traumatic puncture is distinguished by Gradual clearing of the CSF between the 1st and 4th tubes (confirmed by decreasing the red blood cell [RBC] count) Absence of xanthochromia (yellowish CSF due to lysed RBCs) in a centrifuged sample Fresh, uncrenated RBCs With intrinsic subarachnoid hemorrhage, the CSF remains uniformly bloody throughout collection; xanthochromia is often present if several hours have passed after ictus; and RBCs are usually older and crenated. Faintly yellow fluid may also be due to senile chromogens, severe jaundice, or increased protein (>100 mg/dL). 