Stool pH Test

 


🧪 1. Objective

The objective of the test was to determine the pH of stool, which helped evaluate conditions like carbohydrate malabsorption, bacterial overgrowth, or infection in the gastrointestinal tract.

🧪 2. Principle

The test relied on the fact that stool pH reflects the acid-base balance of the intestinal contents. In cases of carbohydrate malabsorption or fermentation, the stool becomes more acidic. The pH was measured either using pH paper or a digital pH meter.

🧪 3. Materials

  • Fresh stool sample in a clean container

  • pH indicator paper (range: pH 4.0–9.0) or digital pH meter

  • Glass stirring rod or applicator stick

  • Distilled water (if needed for preparation)

  • Gloves and PPE

🧪 4. Procedure

  1. A fresh stool sample was collected and brought to room temperature.

  2. A small amount of stool was smeared onto a strip of pH paper.

  3. The color change was compared to the standard color scale on the pH paper packaging.

  4. (Alternatively, a stool suspension was made in distilled water and measured with a calibrated pH meter.)

  5. The pH was recorded immediately.

🧪 5. Result (Example)

ObservationInterpretation
pH 5.0 (acidic)Suggestive of carbohydrate malabsorption
pH 7.0 (neutral)Normal
pH > 8.0 (alkaline)Suggestive of bacterial overgrowth
Example:

Test Result → pH: 5.2
Interpretation → Acidic stool indicating possible lactose intolerance or other carbohydrate malabsorption.

🧪 6. Uses

  • Diagnosed carbohydrate malabsorption (e.g., lactose intolerance)

  • Evaluated chronic diarrhea in infants and children

  • Helped assess intestinal flora changes due to infection or antibiotics

🧪 7. Conclusion

The stool pH test was a simple and rapid bedside tool to screen for intestinal fermentation disorders or malabsorption. It was especially useful in pediatric settings.

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