Reducing Substances
- Sample Type
- Standard
- Fasting
- No
- Unit
- mg/dL
The stool reducing substances test is primarily used to screen for carbohydrate malabsorption, most notably lactose intolerance. In normal digestion, carbohydrates are broken down into monosaccharides by enzymes like lactase and absorbed in the small intestine. If these enzymes are deficient, undigested sugars remain in the lumen, acting as osmotic agents that draw water into the gut (causing diarrhea) and are fermented by bacteria into 'reducing' compounds. This test is critical in pediatric settings to differentiate between viral gastroenteritis and congenital or secondary enzyme deficiencies.
Check Your Result
Check Your Result
Enter your lab result to see where you stand compared to the standard reference range.
Why Context Matters
False negatives can occur if the stool is not fresh (bacteria consume the sugars quickly) or if the patient is on a low-carb diet. Conversely, certain medications (like Vitamin C or Salicylates) or sucrose (which is not a reducing sugar unless first hydrolyzed) can lead to misleading results.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Related Indicators
Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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