Role of seroconversion in confirming cure of Helicobacter pylori infection.

CONTEXT: The role of serologic testing to confirm cure of Helicobacter pylori infection after antimicrobial therapy is not completely defined.

OBJECTIVE

To determine the utility of serologic testing in confirming cure of H pylori infection more than 1 year after therapy.

DESIGN

A prospective, before-after interventional trial.

SETTING

An outpatient clinical research laboratory in an academic, urban Veterans Affairs medical center.

PARTICIPANTS

Twenty-three otherwise healthy men and women with active H pylori infection demonstrated by gastric biopsy and with positive H pylori serologic findings.

INTERVENTION: A 14-day course of bismuth, tetracycline, and metronidazole.

MAIN OUTCOME MEASURES: Determination of IgG serum antibodies to H pylori at baseline, 1 month, 3 months, and approximately 18 months after completion of therapy compared with serial gastric mucosal biopsy specimens with stains for H pylori and for histologic examination as the criterion standard.

RESULTS

Fifteen (65%) of 23 subjects were cured of their H pylori infection as assessed by gastric biopsy, with elimination of gastritis; median antibody levels declined from 92.5 U/mL at baseline to undetectable levels at 18 months. The other 8 subjects (35%) were not cured and had persistent gastritis at 18 months; median antibody levels declined from 130.6 U/mL at baseline to 89.7 U/mL at 18 months. Sensitivity and specificity of seroconversion (from a positive to negative test result) in detecting cure of H pylori infection were 60% and 100%, respectively.

CONCLUSION

Undetectable antibody levels beyond the first year of therapy accurately confirm cure of H pylori infection in initially seropositive healthy subjects, with reasonable sensitivity.