Test for glucosuria ( Benedict's reagent test )

Test for glucosuria ( Benedict's reagent test )

Glucosuria is define is the excretion of sugar in urine.

Apparatus

Benedict's reagent, Test tube, Urine, Lighter, Candle,

Principle

Cupric ion reduced by glucose to cuprous oxide and a coloured precipitate is formed.

Procedure

• In test tube take 5ml of benedict's reagent.
• Add 8 drops or 0.5 ml urine.
• Heat to boiling for two minutes.
• Cool in water bath or running tap water.
• Than look for colour change and precipitation.

Benedict's test

Results

Normally 130 mg / day glucose comes out with urine.

• Blue colour (no change colour ) = Negative
• Greenish colour                          = Traces ( less than 0.5 g /day ).
• Green / cloudy green ppt            = + ( 0.5 - 1 g/dl ).
• Yellow ppt                                  = ++ ( 1-1.5 g / dl ).
• Orange ppt                                  = +++ ( 1.5 - 2 g / 100ml ).
• Brick ppt                                     = ++++ ( more than 2 g / dl ).

Semiquantitative interpretation

Causes

• Diabetes mellitus
• Renal glucosuria
• Severe burns
• Administration of corticosteroids
• Severe sepsis
• Pregnancy