Chromoendoscopy with red phenol in the diagnosis of Helicobacter pylori infection

Abstract

An analytic study to validate a diagnostic test was carried out at the Institute of Gastroenterology in Havana, Cuba in adult patients of both sexes in whom chromoendoscopy was carried out with red phenol at 0.1% over the gastric mucosa for the detection of Helicobacter pylori infection between November 2008 and December 2010. The staining with red phenol at 0.1% is included in the invasive tests for the diagnosis of Helicobacter pylori infection and of the reactive techniques. The sensibility of red phenol dye in the diagnosis of Helicobacter pylori infection in the patients studied was of 72.6% with a confidence interval (C.I.) of 95% (64.9 to 79.2%) and a specificity of 75.5% C.I. 95% (61.9 to 85.4%). The positive predictive value was of 89.8% C.I. 95% (83.1 to 94.1%) and the negative predictive value of 48.1% C.I. 95% (37.3 to 59.0%). The proportion of false positives was of 24.5% C.I. 95% (14.6 to 38.1%) and the proportion of false negatives was of 27.4% C.I. 95% (20.8 to 35.1%). The diagnostic accuracy of the dye on the patients studied was 73.3% C.I. 95% (66.7 to 79.0%). The diagnostic odds ratio was 8.17 C.I. 95% (3.88 to 17.23), the J Youden ratio of 0.5 and the Kappa coefficient of 0.40 C.I. 95% (0.27 to 0.54). The staining dye with red phenol at 0.1% resulted in a useful method in the diagnosis of Helicobacter pylori infection in the gastric mucosa, it can be applied in our environment and has multiple advantages (topographic localization, avoids contamination and fast and immediate reading).

Comparison between phenol red chromo-endoscopy and a stool rapid immunoassay for the diagnosis of Helicobacter pylori in patients with gastritis

“…Such controversy might be due to the difference in sampling technique; as our study the sampling was endoscopic, while they obtained the biopsies after the operation with free access to every part of the stomach. Also Hernández-Garcés et al [ 14 ] study in Cuba on 195 patients showed a phenol red chromo-endoscopy sensitivity of 72.6% and specificity of 75.5% with Kappa coefficient of 0.4, with a positive predictive value of 89.8% and negative predictive value of 48.1% with diagnostic accuracy of 73.3%.…”

Review: Diagnostic accuracy of PCR‐based detection tests for Helicobacter Pylori in stool samples

“…Conflicts were resolved by discussion until consensus was reached. The reviewers were not blind to the journal author names, author affiliations, and year of publication . Two‐by‐two tables were constructed in this study from each gene in all studies for the true‐positive (TP), false‐negative (FN), true‐negative (TN), and false‐positive (FP) values.…”

“…Altogether, histologic identification is a conventional test in the diagnoses of H. pylori infection with a mean sensitivity and specificity of 94% and 99%, respectively . This test is only performed following an endoscopy, and controversially, in a few studies, a lower sensitivity and specificity (73% and 76%, respectively) have been reported . Other tests including UBT, CLO (campylobacter‐like organism test), and PCR are also among the most reliable diagnostic techniques for the detection of H. pylori infection…”

“…In this regard, various specificities and sensitivities have been reported for stool PCR‐based techniques. In addition, researchers have identified H. pylori infection by amplifying different regions of its genome …”

Chromoendoscopy for H. pylori infection: Time for a reaction?

“…In this issue of the Spanish Journal of Gastroenterology, Hernández-Garcés et al (15), from Cuba, report on a study for the validation of a diagnostic test: phenol red chromoendoscopy for the detection of H. pylori infection versus histology as gold standard. Phenol red staining sensitivity was 72.6% and specificity was 75.5%.…”