title: Real-time PCR for diagnosing Helicobacter pylori infection in patients with upper gastrointestinal bleeding: comparison with other classical diagnostic methods.
abstract: The aim of this study was to determine the diagnostic usefulness of quantification of the H. pylori genome in detection of infection in patients with upper gastrointestinal bleeding (UGB). A total of 158 consecutive patients with digestive disorders, 80 of whom had clinical presentation of UGB, were studied. The number of microorganisms was quantified using a real-time PCR system which amplifies the urease gene with an internal control for eliminating the false negatives. A biopsy sample from the antrum and corpus of each patient was processed. The rapid urease test, culture, histological study, stool antigen test, and breath test were done. The gold standard was a positive culture or positive results in at least two of the other techniques. When a positive result was defined as any number of microorganisms/human cell, the sensitivity of real-time PCR was greater in bleeding patients, especially in the gastric corpus: 68.4% (95% confidence interval [CI], 52.3 to 84.5%) in non-UGB patients versus 91.5% (95% CI, 79.6 to 97.6%) in UGB patients. When a positive result was defined as a number of microorganisms/human cell above the optimal value that maximizes the Youden index (>3.56 microorganisms/human cell in the antrum and >2.69 in the corpus), the sensitivity and specificity in UGB patients were over 80% in both antrum and corpus. Our findings suggest that some bleeding patients with infection caused by H. pylori may not be correctly diagnosed by classical methods, and such patients could benefit from the improved diagnosis provided by real-time PCR. However, the clinical significance of a small number of microorganisms in patients with negative results in classical tests should be evaluated.
authors: S. Medicina Digestiva, Hospital General Universitario de Elche, Elche, Alicante, Spain.
authors: Jesús
authors: J
authors: Saez
authors: Sofía
authors: S
authors: Belda
authors: Miguel
authors: M
authors: Santibáñez
authors: Juan Carlos
authors: JC
authors: Rodríguez
authors: Javier
authors: J
authors: Sola-Vera
authors: Antonio
authors: A
authors: Galiana
authors: Montserrat
authors: M
authors: Ruiz-García
authors: Alicia
authors: A
authors: Brotons
authors: Elena
authors: E
authors: López-Girona
authors: Eva
authors: E
authors: Girona
authors: Carlos
authors: C
authors: Sillero
authors: Gloria
authors: G
authors: Royo
mesh_terms: D000328:Adult; D000368:Aged; D001426:Bacterial Proteins / Q000235:genetics; D001431:Bacteriological Techniques / Q000379:methods*; D005260:Female; D006471:Gastrointestinal Hemorrhage / Q000382:microbiology; D016481:Helicobacter Infections / Q000150:complications / Q000175:diagnosis* / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D011446:Prospective Studies; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D014510:Urease / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D014510:Urease