Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.
A 60-year-old woman is evaluated 1 month after completing a 14-day course of Helicobacter pylori eradication therapy consisting of amoxicillin, clarithromycin, and omeprazole. Initial upper endoscopy before treatment showed patchy gastric erythema with no ulcers or erosions, and biopsies revealed H. pylori gastritis. Currently, she reports alleviated symptoms. She is otherwise healthy and takes no medication.
Which of the following is the most appropriate test to perform next?
A. Serologic antibody testing for H. pylori
B. Upper endoscopy with gastric biopsy
C. Urea breath test
D. No further testing
MKSAP Answer and Critique
The correct answer is C. Urea breath test.
A urea breath test is the most appropriate next test for this patient. Testing to confirm eradication should be pursued in all cases of identified and treated Helicobacter pylori infection because of the established risks for peptic ulcer disease and gastric malignancy in patients with chronic H. pylori infection. To maximize the accuracy of testing to confirm eradication, testing should be performed a minimum of 4 weeks after completion of H. pylori eradication therapy and after proton pump inhibitor therapy has been discontinued for 1 to 2 weeks and H2-blockers for 1 to 2 days. The test chosen should be highly accurate in identifying active infection; appropriate tests include the urea breath test, fecal antigen test, or biopsy-based testing. The urea breath test is limited by need for specialized equipment and personnel and by its cost. The fecal antigen test is limited by the collection of stool but is less expensive than the urea breath test. Biopsy-based testing is expensive and invasive. Unless upper endoscopy is indicated for other reasons, noninvasive testing modalities (the urea breath test or the fecal antigen test) are more appropriate for confirmation of eradication or assessment for reinfection. Both testing modalities are equivalent with regard to accuracy; therefore, the specific test chosen should be based on patient preference and/or test availability.
Serologic antibody testing is an inaccurate means of testing to confirm eradication because antibodies can remain present despite successful eradication of active infection; therefore, serologic testing cannot distinguish between past and current H. pylori infection.
Invasive (endoscopic) tests for H. pylori include the rapid urease test, histology, and culture; all invasive testing modalities identify active infection. Due to its expense and invasive nature, biopsy-based testing should be reserved for patients requiring a repeat upper endoscopy for other reasons (for example, follow-up endoscopy for high-risk gastric ulcer). In this patient with no indications for repeat upper endoscopy, one of the two noninvasive tests, either the urea breath test or fecal antigen test, is preferable.
Key Point
- After eradication therapy for Helicobacter pylori infection, eradication should be confirmed using the urea breath test or fecal antigen test.
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