CSF/serum glucose ratio

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

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

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 = 0.4

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.