Observer Homogeneity in the Histologic Diagnosis ofHelicobacter pylori: Latent Class Analysis, Kappa Coefficient, and Repeat Frequency

Abstract

Four pathologists independently examined 82 antral mucosal biopsy specimens for the presence of Helicobacter pylori and indicated whether their assessments were certain. The pathologists made a positive diagnosis in from 56% to 84% of the specimens (significant heterogeneity, p < 0.01). The frequency of uncertain diagnoses was from 4% to 20% (p < 0.01). Uncertain statements occurred more frequently among negative than among positive diagnoses. For the six pairs of observers the kappa coefficients were between 0.39 and 0.82. By a latent class analysis measures of diagnostic accuracy were calculated comparing the observers' assessments with an estimated consensus diagnosis. The predictive values of a positive diagnosis ranged from 0.70 to 1.00. By calculation of repeat frequencies--that is, the probability that an observer's statement was confirmed by another observer--it became evident that uncertain statements were less frequently (61%) confirmed than were certain ones (85%). It is concluded that observer homogeneity is only moderate with regard to the histologic diagnosis of H. pylori, which should be considered both in daily clinical routine and in scientific studies. Disagreement between observers was associated with negative diagnoses, presumably because the pathologists felt more uncertain in these cases.

Fast and Accurate Quantitative Detection of Helicobacter pylori and Identification of Clarithromycin Resistance Mutations in H . pylori Isolates from Gastric Biopsy Specimens by Real-Time PCR

“…Culture is only semiquantitative and is time consuming. Histology is also semiquantitative, but its accurateness is relatively weak because of great interobserver variation (2,6,9). Urea breath test has been shown to be uncorrelated to culture-determined bacterial density ( Our LC-PCR technique was fast.…”

Comparative evaluation of urine-based and other minimally invasive methods for the diagnosis of Helicobacter pylori infection

“…7-10 Initially, the rapid urease test, bacteriological culture, and gastric histological examination, which require endoscopic biopsy, were widely used for diagnosis. [7][8][9][10][11][12][13][14][15][16][17][18][19] Serum antibody assay and the urea breath test (UBT), which do not require endoscopy, are now becoming more frequently used as diagnostic methods. 7-10,20-32 Recently, new methods for the detection of anti-H. pylori antibody in urine and H. pylori antigen in the stool have been developed.…”

Quantitative real-time PCR for the clinical detection of Helicobacter pylori

“…Bacteriological culture and histology allow only the semi-quantitative determination of infection, and both require experienced professionals for their execution and the interpretation of results (Christensen et al, 1992;Atherton et al, 1996;El-Zimaity et al, 1996;Leodolter et al, 2001). On the other hand, the RT-PCR assay can accurately detect and quantify five bacterial cells per 200 ng of human DNA as previously described (Mikula et al, 2003;SchabereiterGurtner et al, 2004).…”