VLD 411: Veterinary Clinical Biochemistry and Laboratory Diagnosis - I (0+1)

GLUCOSE

• Normal urine does not contain glucose. Although glucose passes through the glomerulus, it should be reabsorbed by the proximal convoluted tubules.

Benedict’s test

• Benedict’s qualitative reagent
• Solution-I
  • Cupric sulphate crystals - 17.3 g
    Distilled water - 100 ml
• Solution-II
  • Sodium carbonate - 100 g
    Sodium citrate - 173 g
    Distilled water - 700 ml
• Cool the solution (II) to room temperature and pour into the solution (I), stirring constantly and make up the volume to 1000ml with distilled water.

Principle

• Glucose is a reducing agent, which converts the cupric ions in the copper sulphate to cuprous ions, cuprous oxide.

Procedure: (Click here for animation)

• Take 5 ml of the reagent in a test tube and heat it (the original blue colour of the reagent should not be changed)
• Add 8 drops of urine to it and boil it carefully seeing that it does not spurt while boiling
• Development of greenish, greenish-yellow, yellow or red color is positive for sugar  

Interpretation - Glycosuria

• Emotional stress
• Diabetes mellitus
• Hyperthyroidism
• Acute and chronic pancreatic necrosis
• Hyperpituitarism
• Overactivity of adrenal cortex
• Shock
• Chronic liver disease
• Enterotoxaemia in sheep
• Brain tumors
• Rabies
• False positive reaction for glucose can occur if other reducing agents like antibiotics, lactose, ascorbic acid, salicylates, morphine, formaldehyde and uric acid are present.