Sorted By Test Name - Mayo Medical Laboratories

RGLUR
89847
GLSF
152
GLUR
8412
Glucose, Random, Urine
Clinical Information: Under normal circumstances, glucose is readily filtered by glomeruli and the
filtered glucose is reabsorbed by the proximal tubule; essentially no glucose is normally excreted in the
urine. However, the capacity for the proximal tubule to reabsorb glucose is limited; if the filtered load
exceeds the proximal tubule's reabsorptive capacity, a portion of the filtered glucose will be excreted in
the urine. Thus, elevated serum glucose concentrations (as seen with diabetes mellitus) may result in an
increase in filtered load of glucose and may overwhelm the tubules' reabsorptive capacity resulting in
glucosuria. Glucosuria occurs when the renal threshold for glucose is exceeded (typically >180 mg/dL).
This is most commonly, although not exclusively, seen in diabetes. Additionally, conditions which
adversely affect proximal tubule function may also result in decreased reabsorption of glucose, and
increased urinary glucose concentration, even in the presence of normal plasma glucose concentrations.
Some of these conditions include Fanconi syndrome, Wilson disease, hereditary glucosuria, and
interstitial nephritis. These conditions are relatively rare, and most causes for elevated urine glucose
concentrations are due to elevated serum glucose levels.
Useful For: An indicator of abnormal proximal tubule function Limited usefulness in the screening or
management of diabetes mellitus
Interpretation: Elevated urine glucose concentration reflects either the presence of hyperglycemia or a
defect in proximal tubule function. As a screening test for diabetes mellitus, urine glucose testing has a
low sensitivity (though reasonably good specificity).
Reference Values:
< or =15 mg/dL
Clinical References: Tietz Textbook of Clinical Chemistry, 3rd edition. Edited by CA Burtix, ER
Ashwood. Philadelphia, WB Saunders Company,1999
Glucose, Spinal Fluid
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.
Useful For: Investigating possible central nervous system infection
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.
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.
Clinical References: Tietz Textbook of Clinical Chemistry. 4th edition. Edited by CA Burtis, ER
Ashwood, D Burns. Philadelphia, WB Saunders Company, 2006 pp 837-891
Glucose, Urine
Clinical Information: Under normal circumstances, glucose is readily filtered by glomeruli and the
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