Stool antigen assay (HpSA) is less reliable than urea breath test for post-treatment diagnosis of Helicobacter pylori infection

Aliment Pharmacol Ther. 2002 Oct;16(10):1733-8. doi: 10.1046/j.1365-2036.2002.01345.x.


Background: The diagnostic yield of the stool antigen test (HpSA) in evaluating the results of Helicobacter pylori eradication therapy is controversial, but many studies have used only the 13C-urea breath test (13C-UBT) as a gold standard which has greatly reduced their relevance.

Aim: To compare the reliability of HpSA and 13C-UBT in patients post-treatment using biopsy-based methods as reference tests.

Methods: A total of 100 consecutive dyspeptic patients (42 male and 58 female; mean age, 56 +/- 18 years) were enrolled in our study. All patients were H. pylori positive on the basis of at least two biopsy-based methods, and underwent 1 week of treatment with various triple therapies. They were again endoscoped 4 weeks after completing therapy and six biopsy specimens were taken from the gastric antrum and corpus for rapid urease test, histology and culture. HpSA and 13C-UBT were also performed within 3 days of the second endoscopy.

Results: On the basis of biopsy-based tests, infection was eradicated in 77 patients but continued in 23. Three false negatives were observed with HpSA and two with 13C-UBT. In contrast, the number of false positives was significantly higher (P < 0.01) with HpSA than with 13C-UBT (nine vs. one), confirming the lower specificity of the former test. The overall accuracy of HpSA was 88% vs. 97% for 13C-UBT (P < 0.02).

Conclusions: HpSA has lower diagnostic value than 13C-UBT in the evaluation of the outcome of anti-H. pylori therapy. 13C-UBT remains the first-line diagnostic method to monitor eradication results. The use of HpSA should be reserved for those settings in which 13C-UBT is not available.

Publication types

  • Validation Study

MeSH terms

  • Adult
  • Aged
  • Anti-Bacterial Agents / therapeutic use
  • Antigens, Bacterial / analysis*
  • Biopsy
  • Breath Tests / methods
  • Carbon Isotopes
  • Drug Therapy, Combination
  • Feces / microbiology*
  • Female
  • Helicobacter Infections / diagnosis*
  • Helicobacter Infections / drug therapy
  • Helicobacter pylori / immunology*
  • Humans
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Prospective Studies
  • Sensitivity and Specificity
  • Treatment Outcome


  • Anti-Bacterial Agents
  • Antigens, Bacterial
  • Carbon Isotopes