Use of endoscopic Congo red test in the evaluation of ulcer recurrence risks after proximal gastric vagotomy. A new interpretive method.

The endoscopic Congo red test (ECRT) was performed in 43 patients who underwent proximal gastric vagotomy (PGV) for duodenal ulcer (DU). The aim of the study was to develop a standard and reliable way to interpret the results obtained in this test. Thus, the results of ECRT were related to post-operative clinical evaluation and to pre- and post-operative basal and pentagastrin-stimulated gastric acidity. Whenever ECRT was considered positive, we called it in "large extension" if a red-to-black colour change occurred in three or more of the areas studied. Positive ECRT was observed in 39 patients (90.7%). There was a statistically significant (P less than 0.01) correlation between poor clinical results and positive ECRT in "large extension". We concluded that: (1) a positive ECRT result has no clinical or prognostic significance in DU patients after PGV; (2) ECRT, analysed according to the extension of the areas turning black, is a practical and reliable method to establish clinical results and prognosis in these patients.