Table 1.

Concentrations of solutes in plasma and lumbar CSF in human

Solute	Plasma	CSF
Sodium, mM	150	147
Sodium,* mEq/L	140	144
Potassium, mM	4.63	2.86
Magnesium, mM	0.81	1.12
Calcium, mM	2.35	1.14
Chloride, mM	99	113
Bicarbonate, mM	26.8	23.3
Inorganic phosphate, mg/dL	4.7	3.4
Protein, mg/dL	6,800	28
Glucose, mg/dL	100	50–80
Osmolality, mosmol/kgH2O	289	289
pH	7.397	7.307
pco2, mmHg	41.1	50.5

See Ref. 446. CSF, cerebral spinal fluid. *mEq/liter data for sodium employ actual volumes of respective fluids.