Table 2.

Table Comparing Differences Between Ventricular CSF and Lumbar CSF in States of Health and Disease

Parameter	Ventricular CSF	Lumbar CSF	Normal Physiology	Changes in Pathology
Protein	Lower	Higher	Protein is progressively added through normal CSF circulation. 80% is derived from serum.	Increased ventricular–lumbar gradient in most disease processes; the magnitude of difference varies.
			Normal ventricular:lumbar ratio of 0.25:0.60 in health.
Glucose	Similar	Similar	Similar concentrations in healthy individuals.	Ventricular glucose significantly higher than lumbar glucose in most CNS infections.
			Strong correlation to serum levels of glucose.	Multifactorial mechanisms and varies in disease states. Proposed mechanisms include increased microbial consumption, increased brain metabolic activity, consumption by WBC or malignant cells, and impaired function of the BBB & choroidal plexus.
WBCs	Lower	Higher	WBC gradient exists in health based on limited data. Mechanisms not clear.	Increased gradient in most disease processes, but degree depends on cause and location of abnormality in the CNS.
				Reversal of gradient can occur with predominant ventricular pathology.
Lactate	Similar	Similar	A mild cranio-caudal gradient exists, but much more uniform distribution through all compartments.	Elevated levels from CNS anaerobic glycolysis due to any condition that results in cerebral hypoperfusion, or produced by increased concentration of WBCs.
			Produced within the CSF and generally independent of serum levels.	Retains more uniform distribution even in states of disease.

Abbreviations: BBB, blood brain barrier; CNS, central nervous system; CSF, cerebrospinal fluid; WBC, white blood cell.