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Mayo Test ID GLSF Glucose, Spinal Fluid


Specimen Required


Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions: Centrifuge to remove any cellular material.


Useful For

Investigating possible central nervous system infection

Method Name

Photometric, Glucose Oxidase/Peroxidase

Reporting Name

Glucose, CSF

Specimen Type

CSF

Specimen Minimum Volume

0.25 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
CSF Frozen (preferred) 30 days
  Refrigerated  7 days

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Clinical Information

Cerebrospinal fluid (CSF) is secreted by the choroid plexuses, around the cerebral vessels, and along the walls of the ventricles of the brain, filling the ventricles and cisternae and bathing the spinal cord. CSF is reabsorbed into the blood through the arachnoid villi. CSF turnover is rapid, exchanging about 4 times per day.

 

CSF glucose levels may be decreased due to consumption by microorganisms, impaired glucose transport, or increased glycolysis. Elevated CSF glucose levels are consistent with hyperglycemia.

Reference Values

Spinal fluid glucose concentration should be approximately 60% of the plasma/serum concentration and should be compared with concurrently measured plasma/serum glucose for adequate clinical interpretation.

 

For SI unit Reference Values, see https://www.mayocliniclabs.com/order-tests/si-unit-conversion.html

Interpretation

Cerebrospinal fluid (CSF) glucose levels may be decreased in any central nervous system infection, although levels are typically normal in viral meningitis, low in bacterial meningitis, and may be normal or low in fungal meningitis.

 

CSF glucose levels are normally about 60% of blood glucose levels.

Cautions

Handle specimens in stoppered containers to avoid contamination and evaporation.

 

Cerebrospinal fluid specimens should be processed without delay; they may contain cellular constituents, as well as organisms, that lower the concentration of glucose with time.

Clinical Reference

Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Edited by CA Burtis, ER Ashwood, DE Bruns, St. Louis, MO, Elsevier Saunders, 2012

Method Description

Patient specimen is deposited on the slide where the spreading layer promotes the uniform distribution of the specimen and permits an even penetration of solute molecules into the underlying reagent layer. The oxidation of specimen glucose is catalyzed by glucose oxidase to form hydrogen peroxide and gluconate. The reaction is followed by an oxidative coupling catalyzed by peroxidase in the presence of dye precursors to produce a dye. The intensity of the dye is measured by reflected light.

 

Each mole of glucose oxidized results in 0.5 mole of dye, assuming quantitative conversions. The intensity of the dye is measured by reflected light at 540 nm and concentration is reported in milligrams per deciliter.(Package insert: Vitros Chemistry Products Instructions for Use-GLU Slides, Ortho-Clinical Diagnostics, Inc. Rochester, NY 14626)

Day(s) Performed

Monday through Sunday

Report Available

Same day/1 day

Specimen Retention Time

1 week

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

82945

LOINC Code Information

Test ID Test Order Name Order LOINC Value
GLSF Glucose, CSF 2342-4

 

Result ID Test Result Name Result LOINC Value
GLSF Glucose, CSF 2342-4