Stool pH
Stool pH measures how acidic or alkaline your stool is. It reflects how carbohydrates are being fermented and absorbed in your digestive tract.
An unusually acidic stool can be a clue that sugars aren't being absorbed well, such as in carbohydrate or lactose malabsorption. This test is sometimes used, especially in children, to help investigate chronic diarrhea.
A more alkaline (higher) stool pH is less commonly flagged but may accompany certain infections or shifts in gut bacteria. As with any single measure, it's most meaningful when read alongside symptoms and other results.
A low (acidic) stool pH can suggest that carbohydrates or sugars aren't being fully absorbed, sometimes seen with lactose intolerance or other malabsorption.
A near-neutral stool pH is often considered typical, but normal ranges vary by lab and age. Your clinician can interpret an out-of-range value in the context of your digestion and symptoms.
Sources
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.