ORIGINAL ARTICLE Diagnostic Utility of Invasive Tests and Serology for the Diagnosis of Helicobacter pylori Infection in Different Clinical Presentations Jaime Rau ´l Zu ´n ˜iga-Noriega, a Francisco Javier Bosques-Padilla, a Guillermo Ignacio Pe ´rez-Pe ´rez, b Rolando Tijerina-Menchaca, c Juan Pablo Flores-Gutie ´rrez, d He ´ctor Jesu ´s Maldonado Garza, a and Elvira Garza-Gonza ´lez c a Servicio de Gastroenterologı ´a del Hospital Universitario Dr. Jose ´ Eleuterio Gonza ´lez, Monterrey, Nuevo Leo ´n, Me ´xico b Departments of Medicine and Microbiology, New York University School of Medicine, New York, NY c Departamento de Microbiologı ´a de la Facultad de Medicina, Universidad Auto ´noma de Nuevo Leo ´n, Monterrey, Nuevo Leo ´n, Me ´xico d Laboratorio de Anatomı ´a Patolo ´ gica, Hospital Universitario Dr. Jose ´ Eleuterio Gonza ´lez, Monterrey, Nuevo Leo ´n, Me ´xico Received for publication August 18, 2004; accepted April 27, 2005 (ARCMED-D-04-00060). Background. Invasive and noninvasive tests are used for the diagnosis of Helicobacter pylori infection. The aim of this study was to determine the diagnostic utility of rapid urease test (RUT), culture, histology and serology for the diagnosis of H. pylori in patients with different clinical presentations. Methods. We studied 527 consecutive patients (mean age, 52.5 years; F:M, 1.3; age range 15–89 years) enrolled at the Hospital Universitario, Universidad Auto ´noma de Nuevo Leo ´ n. Patients had gastric cancer (GC, 9.1%), non-ulcer dyspepsia (NUD, 81.4%), or peptic ulcer disease (PUD, 9.1%). The infection by H. pylori was determined by histology, rapid urease test, culture, and serology. Patients were determined as infected with H. pylori if at least a) two invasive tests were positive and b) two tests were positive (invasive or non-invasive). Diagnostic utility was calculated for each assay. Results. Prevalence of infection in the whole studied population was 50.9%. In NUD patients the prevalence was 51.3%, in PUD patients 58.3%, and in GC patients 39.6%. When we used the first diagnostic criteria, for the whole studied population, the RUT was the most reliable test, followed by the culture. Histology had the best sensitivity for the whole studied population and NUD patients and RUT had the best sensitivity value for the GC patients. In the whole studied population, NUD and GC patients, RUT and culture had the best specificity, accuracy and PPV. For PUD patients, serology had the best performance. When we used the second diagnostic criteria, histology and serology had a better performance compared with the results obtained with the first diagnostic criteria. Conclusions. Diagnostic utility of the tests varies according to the clinical presentations, which should be considered in the selection of the diagnostic test for the detection of H. pylori. Ó 2006 IMSS. Published by Elsevier Inc. Key Words: Helicobacter, Serology, Diagnosis, Diagnostic, RUT, Culture. Introduction Infection by Helicobacter pylori is associated with the development of superficial chronic gastritis, gastric or duodenal ulcers, and distal gastric cancer (GC). According to the evidence, H. pylori has been recognized by the World Health Organization (WHO) as a class I gastric carcinogen (1–3). Several diagnostic methods for detecting H. pylori are available. These tests can be divided into invasive methods [rapid urease test (RUT), histology, culture and polymerase chain reaction (PCR)] that require endoscopy; and noninvasive tests, mainly urea breath test (UBT), Address reprint requests to: Elvira Garza-Gonza ´lez, Departamento de Microbiologı ´a de la Facultad de Medicina, Universidad Auto ´noma de Nuevo Leo ´n, Av. Madero y Dr. Aguirre s/n, Colonia Mitras Centro, 64460, Monterrey, Nuevo Leo ´n, Me ´xico; E-mail: elvira_garza_gzz@yahoo.com 0188-4409/06 $–see front matter. Copyright Ó 2006 IMSS. Published by Elsevier Inc. doi: 10.1016/j.arcmed.2005.04.020 Archives of Medical Research 37 (2006) 123–128