BACKGROUND:

Stool form scales are a simple method of assessing intestinal transit rate but are not widely used in clinical practice or research, possibly because of the lack of evidence that they are responsive to changes in transit time. We set out to assess the responsiveness of the Bristol stool form scale to change in transit time.

METHODS:

Sixty-six volunteers had their whole-gut transit time (WGTT) measured with radiopaque marker pellets and their stools weighed, and they kept a diary of their stool form on a 7-point scale and of their defecatory frequency. WGTT was then altered with senna and loperamide, and the measurements were repeated.

RESULTS:

The base-line WGTT measurements correlated with defecatory frequency (r = 0.35, P = 0.005) and with stool output (r = -0.41, P = 0.001) but best with stool form (r = -0.54, P < 0.001). When the volunteers took senna (n = 44), the WGTT decreased, whereas defecatory frequency, stool form score, and stool output increased (all, P < 0.001). With loperamide (n = 43) all measurements changed in the opposite direction. Change in WGTT from base line correlated with change in defecatory frequency (r = 0.41, P < 0.001) and with change in stool output (n = -0.54, P < 0.001) but best with change in stool form (r = -0.65, P < 0.001).

CONCLUSIONS:

This study has shown that a stool form scale can be used to monitor change in intestinal function. Such scales have utility in both clinical practice and research.