CSF/serum glucose ratio

CSF/serum glucose ratio
Reference range	0.6
LOINC	2352-3

The CSF/serum glucose ratio, also known as CSF/blood glucose ratio, is a measurement used to compare CSF glucose and blood sugar.

Because many bacteria metabolize glucose, and because the blood–brain barrier minimizes transversal, the ratio can be useful in determining whether there is a bacterial infection in the CSF.

The normal ratio is 0.6.^[1]

It is used to distinguish between bacterial and viral meningitis, as it is often lowered in bacterial meningitis and normal in viral meningitis.^[2]

References

Pathophysiology sample values

BMP/ELECTROLYTES:
Na^+ = 140	Cl^− = 100	BUN = 20	/ Glu = 150 \
K^+ = 4	CO2 = 22	PCr = 1.0
ARTERIAL BLOOD GAS:
HCO3^− = 24	paCO2 = 40	paO2 = 95	pH = 7.40
ALVEOLAR GAS:
	pACO2 = 36	pAO2 = 105	A-a g = 10
OTHER:
Ca = 9.5	Mg^2+ = 2.0	PO4 = 1
CK = 55	BE = −0.36	AG = 16
SERUM OSMOLARITY/RENAL:
PMO = 300	PCO = 295	POG = 5	BUN:Cr = 20
URINALYSIS:
UNa^+ = 80	UCl^− = 100	UAG = 5	FENa = 0.95
UK^+ = 25	USG = 1.01	UCr = 60	UO = 800
PROTEIN/GI/LIVER FUNCTION TESTS:
LDH = 100	TP = 7.6	AST = 25	TBIL = 0.7
ALP = 71	Alb = 4.0	ALT = 40	BC = 0.5
		AST/ALT = 0.6	BU = 0.2
AF alb = 3.0	SAAG = 1.0		SOG = 60
CSF:
CSF alb = 30	CSF glu = 60	CSF/S alb = 7.5	CSF/S glu = 0.6

1. Karen Roos (2005). Principles of neurologic infectious diseases. New York: McGraw-Hill, Medical Pub. Division. p. 4. ISBN 0-07-140816-9.
2. Tamune H; et al. (2014). "Cerebrospinal fluid/blood glucose ratio as an indicator for bacterial meningitis". Am J Emerg Med. 32 (3): 263–6. doi:10.1016/j.ajem.2013.11.030. PMID 24361137.