Stool Reducing Substance Test

The Stool Reducing Substance (SRS) test is used to check for the presence of unabsorbed sugars (carbohydrates) in the stool. It helps diagnose carbohydrate malabsorption, commonly seen in conditions like lactose intolerance and other sugar digestion disorders.

Why is it done?

A doctor may recommend this test if a patient has:
✅ Chronic diarrhea (especially in infants)
✅ Bloating, gas, or abdominal cramps
✅ Failure to gain weight in infants or children
✅ Suspected lactose intolerance or sugar malabsorption

What does it check for?

This test detects reducing sugars (like lactose, glucose, fructose, galactose) in stool, which indicates that they are not being properly absorbed in the intestines.

Test Procedure

1. Sample Collection:

   • A fresh stool sample is collected in a sterile container.
   • The sample should not be contaminated with urine or water.
   • It is sent to the lab for testing.

2. Benedict’s Test:

   • The sample is mixed with Benedict’s reagent.
   • If reducing sugars are present, the solution changes color (from blue to green, yellow, or red, depending on sugar levels).

Normal vs. Abnormal Results

If Positive, Possible Causes:
🔴 Lactose intolerance (inability to digest lactose, common in infants and adults)
🔴 Carbohydrate malabsorption syndromes (e.g., glucose-galactose malabsorption)
🔴 Celiac disease (gluten-related digestive disorder)
🔴 Viral or bacterial infections (damaging intestinal lining and affecting sugar absorption)

Next Steps After a Positive Test

📌 Additional tests may be needed, such as:

• Lactose tolerance test (for lactose intolerance)
• Hydrogen breath test (to check sugar digestion)
• Endoscopy and biopsy (if celiac disease is suspected)

How to Reduce Reducing Substances in Stool?

✅ Avoid lactose-containing foods (if lactose intolerance is confirmed)
✅ Use lactose-free formula for infants
✅ Treat underlying infections or digestive conditions
✅ Consult a doctor for dietary adjustments