Urine Glucose

Glucose is measured on the Multistix by a glucose oxidase method. The reaction of glucose with glucose oxidase forms nascent oxygen (O), which converts potassium iodide in the dipstick pad to iodine, forming a brown color change. Normal urinary glucose is below the level of sensitivity of the commonly used detection techniques. Therefore, glucose is an abnormal finding in urine.

False positive reactions

• The presence of hydrogen peroxide, bacterial peroxidases (e.g. cystitis), hypochlorite and chlorine will produce false positive reactions.
• Formaldehyde
• Outdated reagents

• High concentrations of ascorbic acid inhibit the reaction.
• Drugs: salicylates, tetracyclines.

• Hyperglycemia
  In nearly all cases, glucosuria is a result of prior (often, continuing) hyperglycemia to a level in excess of the renal threshold for reabsorption.
  
  

  Species	Threshold
  Canine	180-200 mg/dL
  Feline	280 mg/dL
  Bovine	100-140 mg/dL
  Equine	160-200 mg/dL

  
  1. Persistent hyperglycemia: Glucosuria is seen in diabetes mellitus, hyperadrenocorticism, acromegaly, phaechromocytoma. Remember that a 4+ glucosuria will increase the USG by 0.010.
  2. Transient hyperglycemia: Stress-related hyperglycemia above the renal threshold will result in glucosuria. This is especially true in cats, which develop marked stress-related hyperglycemias, and where the finding of glucosuria is not diagnostic for diabetes mellitus. Other conditions which produce transient hyperglycemia, e.g. pancreatitis, may induce a mild, transient glucosuria. Note also that a transient glucosuria may be seen 1-2 hours after a heavy meal.
  
  
• Abnormal proximal renal tubule function
  Glucose is absorbed by a carrier-mediated process in the proximal renal tubules. Abnormal tubular function can result in glucosuria without hyperglycemia, but these conditions are quite rare.
  1. Physiologic: Young puppies (< 8 weeks old) can have mild glucosuria due to tubule immaturity.
  2. Renal tubule damage: This could be due to drugs (aminoglycosides), hypoxia, infections (Clostridium perfringens type D in sheep [pulpy kidney]) or idiopathic (proximal renal tubular acidosis).
  3. Inherited renal diseases: Primary renal glucosuria, Fanconi syndrome, etc.

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Last Updated: Friday, January 15th, 1999