ANSWER: C
Critique
The diagnosis of H. pylori may be made using either invasive or noninvasive methods. Invasive diagnostic methods either detect organisms directly (i.e., histological identification with appropriate stains or bacterial culture) or indirectly (i.e., rapid urease testing of biopsy specimens). Noninvasive methods include serum antibody, stool antigen, and detecting the metabolites of the bacterial enzyme urease (i.e., urea breath testing). It should be noted that serology should not be used to test for eradication as the antibodies may remain elevated for years after successful eradication therapy.
Treatment of H. pylori infection has become problematic recently primarily because of increasing antibiotic resistance. The eradication rate of standard triple therapy consisting of a PPI combined with clarithromycin (500 mg) and amoxicillin (1 g) (or metronidazole (500 mg)), all given b.i.d. for 7-14 days has now declined to unacceptable levels, averaging 70%-80% but reported to be as low as 55%. It is currently recommended that a noninvasive method be used (other than serology) to confirm eradication in patients in whom eradication is deemed necessary.
