Noninvasive tests as a substitute for histology in the diagnosis of Helicobacter pylori infection.

Abstract

BACKGROUND:

Rapid urease tests for Helicobacter pylori have a sensitivity of 80% to 90%. Therefore histologic examination of gastric biopsies is recommended as a "backup" diagnostic test in rapid urease test-negative patients. However, noninvasive tests (urea breath test, serology, whole blood antibody tests) may provide a more rapid diagnosis and be less expensive but offer similar accuracy.

METHODS:

Sixty-seven patients (no prior treatment for H pylori, no proton pump inhibitors, antibiotics, or bismuth within 4 weeks) undergoing endoscopy for evaluation of dyspepsia symptoms and testing rapid urease test-negative by antral biopsy were enrolled. All had the following tests: gastric biopsies (2 antral, 1 fundus; H&E and Alcian Yellow stain) examined for gastritis and H pylori; (13)C-UBT; capillary blood for whole blood rapid antibody tests: FlexSure HP, QuickVue, AccuStat, and Stat-Simple Pylori; serum for FlexSure HP; HM-CAP enzyme-linked immunoassay. H pylori infection was diagnosed (reference standard) if chronic gastritis was present on histology and at least 2 of the 3 following tests were positive: urea breath test, H pylori organisms unequivocally demonstrated in biopsies on special stain, and/or enzyme-linked immunoassay. The test and treatment costs per patient were calculated.

RESULTS:

Of 67 patients with a negative rapid urease test, 4 were positive for H pylori. None had active peptic ulcer disease. Histology only identified 1 patient with organisms visible on special stain. Using chronic active gastritis (neutrophilic and mononuclear infiltrate) as a diagnostic criterion for H pylori, 6 patients would have been judged positive. However, only 2 of these were truly positive by the reference standard (positive predictive value 33%). Negative predictive value for presence of organisms and chronic active gastritis was 95% and 97%, respectively. All of the noninvasive tests identified all 4 truly positive patients correctly. Urea breath test and FlexSure whole blood assay yielded a substantial number of false-positive results (positive predictive value 31% and 36%, respectively); positive predictive value for the other tests ranged from 50% to 80%. All tests except histology had a negative predictive value of 100%. Histology was the most costly test (p < 0. 001 compared with all other tests), followed by urea breath test and HM-CAP serology (p < 0.001 compared with all rapid antibody tests).

CONCLUSIONS:

Whole blood or serum antibody testing is a rapid, accurate, and cost-effective means for establishing H pylori status in rapid urease test-negative patients. Whole blood or serology rapid antibody testing should substitute for histology when the patient has not been previously treated for H pylori.

• Authors: M Hahn, M B Fennerty, C L Corless, N Magaret, D A Lieberman, D O Faigel
• Journal: Gastrointestinal endoscopy (Gastrointest Endosc) Vol. 52 Issue 1 Pg. 20-6 (Jul 2000) ISSN: 0016-5107 [Print] United States
• PMID: 10882957 (Publication Type: Clinical Trial, Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies, Bacterial
• Urea

Topics

• Adult
• Aged
• Aged, 80 and over
• Antibodies, Bacterial (analysis)
• Biopsy, Needle
• Breath Tests
• Cost-Benefit Analysis
• Female
• Gastritis (microbiology, pathology)
• Gastroscopy
• Helicobacter Infections (diagnosis, pathology)
• Helicobacter pylori (isolation & purification)
• Humans
• Immunoenzyme Techniques (economics)
• Male
• Middle Aged
• Probability
• Prospective Studies
• Sensitivity and Specificity
• Urea (analysis)