URINE GLUCOSE

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. The table below illustrates how results from the dipstick (Multistix) correlates to those from the Criterion, the machine used to "read" the dipstick at Cornell University. Multistix Criterion Neg Neg Trace (100 mg/dL, 1/10) 50 mg/dL Small (250 mg/dL, 1/4) 100 mg/dL Moderate (500 mg/dL, 1/2) 250 mg/dL Large (1000 mg/dL, 1) ≥1000 mg/dL Large (>2000 mg/dL, ≥2) ≥1000 mg/dL False positive reactions The presence of hydrogen peroxide, bacterial peroxidases (e.g. cystitis), hypochlorite and chlorine will produce false positive reactions. Formaldehyde Outdated reagents False negative reactions High concentrations of ascorbic acid inhibit the reaction. Drugs: salicylates, tetracyclines. Pathologic glucosuria 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 180-220 mg/dL Feline 280-290 mg/dL Bovine 100-140 mg/dL Equine 150-160 mg/dL 1. Persistent hyperglycemia: Glucosuria is seen in diabetes mellitus, hyperadrenocorticism, acromegaly, and phaechromocytoma. Remember that a 4+ glucosuria will increase the USG by 0.010 units. 2. Transient hyperglycemia: Stress-related hyperglycemia above the renal threshold will result in glucosuria. This is especially true in cats and cattle, 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. Source : © Cornell University