Modified Endoscopic Congo Red Test: A Rapid Method to Visualize Gastric Acid Secretion

Abstract

Background: The conventional endoscopic Congo red test (CRT) permits visualization of acid‐producing mucosa. However, the CRT has not been disseminated into clinical endoscopy, which is partly due to the substantial prolongation of the gastroscopic examination. Methods: Five healthy volunteers and 551 patients were included in a study designed to develop a more rapid approach based on the CRT. In this modified endoscopic Congo red test (MCRT), 0.2 µg/kg of pentagastrin was given intravenously to stimulate gastric acid production. The technical feasibility, tolerability, reproducibility, and inter‐ and intra‐observer reliability of the MCRT were evaluated. Results: The MCRT was as effective as the CRT (i.e. 6 µg/kg of pentagastrin was administered intramuscularly) in visualizing the extent of acid‐producing gastric mucosa. Moreover, the MCRT significantly reduced the duration of examination by 63% (almost 8 min), compared to the CRT. Conclusions: This MCRT is a simple, inexpensive, well‐tolerated and reproducible method with low inter‐ and intra‐observer variability and is well suited for endoscopy units with high workloads.

Review article: methods of measuring gastric acid secretion

“…The Modified Congo Red Test (MRCT) was described by Toth et al in 2003. 39 In this test, pentagastrin was given intravenously (0.2 lg ⁄ kg) instead of intramuscularly as was the case with the original method, and this considerably shortened the duration of the examination. However, these tests not only involve endoscopy but also do not provide quantitative measurements of gastric acid and hence are not widely used.…”