H pylori testing

Tests such as faecal antigen assay, urea breath test, rapid urease test, and histology of a biopsy specimen can confirm the diagnosis of H pylori infection. (1)

Both the urea breath test and the faecal antigen test are highly sensitive and specific assays for active H pylori infection. They can also be used to monitor response to therapy. (2)

The H pylori urea breath test has >90% sensitivity and 96% specificity for presence of active infection. (1) It is generally recommended that, in the post-treatment setting, PPIs are withheld for 7-14 days and antibiotics and bismuth withheld for at least 28 days prior to use of the urea breath test to assess H pylori eradication. (2)

The H pylori faecal antigen test identifies H pylori antigen in the stool to diagnose active infection. Both monoclonal and polyclonal assays are available, each with >90% sensitivity and specificity; monoclonal assay has a sensitivity of 96% and a specificity of 97%. (3)

Note - serological tests are of no value in confirming successful eradication, as the antibody persists long after successful eradication. C-urea breath tests and stool antigen tests are generally more accurate than serological tests and they can be used both pre- and post-treatment

UK HSA guidance states (4)

Preferred tests for H pylori:

• Urea breath tests and stool antigen tests (SATs) are the preferred tests
  • UBT or SAT should not be performed within two weeks of PPI, or four weeks of antibiotics, as these drugs supress bacteria and can lead to false negatives

Results:

• if H pylori positive, then treatment is indicated
• if negative test then 
  • only retest for HP if DU, GU, family history of cancer, MALToma, or if test was performed within two weeks of PPI, or four weeks of antibiotics (NPV of all tests is >95%)

Reference

1. Miller JM, Binnicker MJ, Campbell S, et al. Guide to utilization of the microbiology laboratory for diagnosis of infectious diseases: 2024 update by the Infectious Diseases Society of America (IDSA) and the American Society for Microbiology (ASM). Clin Infect Dis. 2024 Mar 5
2. Chey WD, Howden CW, Moss SF, et al. ACG clinical guideline: treatment of Helicobacter pylori Infection. Am J Gastroenterol. 2024 Sep 1;119(9):1730-53.
3. Gisbert JP, Pajares JM. Stool antigen test for the diagnosis of Helicobacter pylori infection: a systematic review. Helicobacter. 2004 Aug;9(4):347-68.
4. UK Health Security Agency. Helicobacter pylori in dyspepsia: test and treat. A quick reference guide for primary care on how to test for and treat Helicobacter pylori (H. pylori) in dyspepsia. Last updated May 2025 (online)