When should Helicobacter pylori (H. pylori) infection be retested after treatment?

From the Guidelines

Retesting for Helicobacter pylori (H. pylori) infection should be performed at least 6 weeks after completion of treatment and at least 2 weeks after proton pump inhibitor (PPI) withdrawal. This waiting period is crucial because testing too early can lead to false negative results 1. The most accurate method for confirming eradication is the urea breath test or stool antigen test, though endoscopic biopsy can also be used in patients requiring follow-up endoscopy. It's essential to stop PPIs at least 2 weeks before testing and antibiotics at least 4 weeks before testing, as these medications can interfere with test accuracy by suppressing H. pylori without completely eradicating it. Retesting is particularly important for patients with persistent symptoms, complicated ulcers, MALT lymphoma, or after treatment for early gastric cancer. The rationale for confirming eradication is that persistent infection can lead to continued inflammation, ulcer recurrence, and increased risk of gastric cancer in susceptible individuals. If the test shows treatment failure, a different antibiotic regimen should be prescribed based on antibiotic resistance patterns or prior treatment history.

Some key points to consider:

• The choice of treatment regimen should be based on the knowledge of the underlying prevalence of resistant strains in the community 1.
• Bismuth quadruple therapy is encouraged particularly in areas of high dual resistance to clarithromycin and metronidazole, and concomitant therapy is appropriate for those patients from areas of high clarithromycin resistance where bismuth is not available 1.
• The duration of first-line therapies is recommended to be 14 days for all first-line treatments, unless 10 days has been proven locally to be as effective for quadruple therapies 1.
• Levofloxacin therapy is not a first-line option for most patients, but can be considered in a patient from an area of high dual (clarithromycin and metronidazole) and low levofloxacin resistance if bismuth is not available 1.

Overall, the goal of retesting is to confirm eradication of H. pylori infection and prevent long-term complications, and the choice of treatment regimen and testing method should be individualized based on patient factors and local resistance patterns.

From the Research

Retesting for H. pylori Infection After Treatment

• The timing of retesting for H. pylori infection after treatment is crucial for accurate assessment of eradication 2, 3, 4.
• According to studies, retesting should be performed at least 4 weeks after completion of treatment to ensure accurate results 2, 3, 4.
• The stool antigen test can be used to predict eradication as early as 7 days after treatment, but it is recommended to confirm eradication at 4 weeks or more after treatment 2.
• The urea breath test is a sensitive indicator of H. pylori eradication and can be used 6 weeks after treatment to confirm eradication 3.
• Setting a grey zone for the 13C-urea breath test at a level of 2.5 to 5.0/1000 can help avoid false-positive results and improve the accuracy of the test for assessing eradication of H. pylori infection 4.

Diagnostic Tests for H. pylori Infection

• Noninvasive diagnostic tests such as the urea breath test and stool antigen assay are recommended for confirming eradication of H. pylori infection 5, 2.
• The urea breath test has a sensitivity of 94% and a specificity of 100% for detecting H. pylori infection 2.
• The stool antigen test has a sensitivity of 94% and a specificity of 97% for detecting H. pylori infection 2.

Treatment and Eradication of H. pylori Infection

• Quadruple therapy (bismuth, metronidazole, and tetracycline plus a proton pump inhibitor) is effective for treating H. pylori infection, but its effectiveness can be reduced by metronidazole resistance 6.
• Sequential therapy (PPI plus amoxicillin followed by a PPI plus clarithromycin plus metronidazole) is a promising approach for treating H. pylori infection 5.
• Confirmation of eradication using noninvasive diagnostic tests is now the standard of care for H. pylori infection 5.