When patients present with symptoms of gastrointestinal (GI) bleeding, it is imperative that physicians determine the site of the bleeding. Bright red fecal blood, hematochezia, is more likely to come from a source near the anus than dark red or maroon fecal blood. In the case of patients with hematochezia, some authors recommend using a 60-cm flexible sigmoidoscopy as the only diagnostic procedure. However, physicians using this strategy risk overlooking a proximal colon lesion as the site of the bleeding. Fine and colleagues researched the association between bright red hematochezia and the site of GI bleeding to determine if these lesions were all within the reach of a 60-cm flexible sigmoidoscope.

All patients who presented with recent or ongoing hematochezia were eligible for the study. The blood had to have some essence of red and had to have been passed in the commode. Patients with blood present only on tissue were excluded from the study. A history of GI bleeding was obtained before any diagnostic procedure was performed. Patients with melena were excluded from the study. The history included questions about the color of the blood, using a four-color card to help patients delineate between bright red, dark red, maroon and black. All patients were then evaluated with colonoscopy to determine the site of bleeding.

Of the 312 patients included in the study, 217 were found to have bright red hematochezia according to the color chart. Of these, 181 had bleeding sites within the first 60 cm of the distal colon. However, 20 patients had more proximal lesions that were not within the reach of the standard flexible sigmoidoscope, with eight cancers discovered. In 16 of the patients, no identifiable source of bleeding was found. Of the 181 patients, 140 would have required colonoscopy to complete the evaluation of the colon in search of a cause of bleeding.

The authors conclude that the evaluation of hematochezia should begin with a complete colonoscopic examination even in patients who report bright red blood. This process would be more effective and would reduce the number of flexible sigmoidoscopies that had to be followed by colonoscopy to complete the evaluation as well as reducing the total cost of the evaluation of patients with hematochezia.