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).