Urine analysis - Reducing Sugar

Topic: Urine analysis - Reducing Sugar
Course: MLT, ATOT, Allied
Faculty: Pathology

1. Urine Analysis: Sugars
Dr. Salman Ansari
Dept. of Pathology
Kanachur Institute of Medical Sciences

2. Contents
●Intro
●Test
●Principle
●Procedure
●Interpretation
●Viva

3. Reducing sugar
Called “reducing” because it has a free ketone or
aldehyde group which can be donated
Examples of reducing sugar:
-Glucose
-fructose

4. Reason to test?
-Presence of detectable amount reducing sugar in urine -
called “glycosuria”
-Presence of detectable amount of glucose in urine -
called “glucosuria”

5. Causes of glucosuria:
-Type 2 Diabetes Mellitus
-Pregnancy : Gestational diabetes mellitus(GDM)
-Severe burns
-IV corticosteroids
-Severe sepsis

6. Test for reducing sugar
Benedict’s test:
-Test to detect reducing sugars in urine
-It is a qualitative test and also semi-quantitative test
-Benedict’s reagentcontains:
-Copper sulphate
-Sodium carbonate
-Sodium citrate

7. Principle
●Urine is added to blue coloured copper sulphate
solution.
●Cupric ion is reduced by glucose to cuprous oxide and
a coloured precipitate is formed.

8. ●Take 5 ml of Benedict’s qualitative reagentin a test
tube.
●Add 8 drops (or 0.5 ml) of urine.
●Heat to boiling for 2 minutes
●Look for colour change
Procedure

10. Interpretation
No change of blue colour = Negative
Greenish colour = Traces (< 0.5 g/dl)
Green/cloudy green ppt = + (0.5-1 g/dl)
Yellow ppt = ++ (1-1.5 g/dl)
Orange ppt = +++ (1.5-2 g/dl)
Brick red ppt = ++++ (> 2 g/dl)

12. Report:
The given sample contains: reducing sugar
Principle Observation Interpretation
0.5 ml of urine boiled
in 5 ml of Benedict’s
reagent.
Blue colour copper
sulphate is reduced in
the presence of
reducing sugar,
leading to colour
change
Orange colour seenReducing sugar
present

13. Viva questions
Q: What does Benedict’s test detect?
Q: What does Benedict’s reagent contain?
Q: What is the principle and procedure of Benedict’s
test?
Q: What are the advantages of Benedict’s test?
-Simple, can be performed quickly
-Cheap
-It is both qualitative and quantitative

14. Q: What are the limitations of Benedict’s test?
-False positive due to drugs like penicillin, isoniazid,
streptomycin, salicylate
-Exact concentration cannot be measured, only
rough estimate

15. References:
●Harsh Mohan -Practical Pathology -5th edition
Questions:
[email protected]
For PPT, scan: