Can Serology Confirm H. pylori Eradication?
September 30, 1998
Can Serology Confirm H. pylori Eradication?
ABSTRACT & COMMENTARY
Synopsis: An undetectable antibody level beyond the first year of therapy accurately confirmed cure of H. pylori infection in initially seropositive healthy subjects.
Source: Feldman M, et al. JAMA 1998;280:363-365.
Feldman and colleagues set out to determine the ability of serologic testing to confirm cure of Helicobacter pylori infection more than one-year after therapy. Twenty-three otherwise healthy men and women with active H. pylori infection demonstrated by gastric biopsy and with positive H. pylori serologic findings were treated with a 14-day course of bismuth, tetracycline, and metronidazole. Thereafter, IgG serum antibodies to H. pylori were determined at baseline and one month, three months, and 18 months following completion of therapy and compared with serial gastric mucosal biopsy specimens submitted for stains for H. pylori and histological examination. The latter were regarded as the gold standard. At 18-months, 15 of the 23 subjects were cured of their H. pylori infection as determined by gastric biopsy. Gastritis was eliminated, and the median antibody levels had declined from 92.5 units at baseline to undetectable. The other eight subjects were not cured and had persistent gastritis at 18 months. Median antibody levels declined from 130.6 at baseline to 89.7 at 18 months. They calculated a sensitivity and specificity of seroconversion in detecting cure of H. pylori infection at 50% and 100%, respectively. The authors concluded that an undetectable antibody level beyond the first year of therapy accurately confirmed cure of H. pylori infection in initially seropositive healthy subjects.
COMMENT BY EAMONN M.M. QUIGLEY, MD
If Helicobacter pylori infection is detected in association with significant upper gastrointestinal mucosal disease, and it is decided to treat the patient in order to eradicate H. pylori, then it makes sense to confirm eradication at some time thereafter. This can be confirmed by repeating endoscopy and obtaining biopsy specimens for either a rapid urease test or for histology and even for culture of H. pylori. These approaches are invasive and expensive. Their widespread application to all receiving therapy for H. pylori would prove enormously expensive. Recently, a breath test has been introduced which appears reasonably sensitive and specific in detecting H. pylori eradication following therapy. The cheapest test of H. pylori infection, namely serology, while the most cost-effective means of establishing the diagnosis of H. pylori, has been criticized because of problems in confirming eradication. The basic problem has been that serology has been found to remain positive for several months, or even up to a year, in some patients who have been successfully eradicated (as indicated by some of the more gold standard tests). This study indicates that where serologic titers have fallen to undetectable levels at 18 months following therapy, this finding is 100% specific for eradication of H. pylori infection. This is certainly an improvement over the rates of 80-90% quoted for serology six months following completion of therapy. These findings are of considerable importance to the primary care physician, but some caution appears appropriate. This is a small sample (only 23 subjects), and these were otherwise healthy individuals without other significant gastrointestinal pathology. These findings clearly need to be replicated in a larger subset of individuals encompassing the entire spectrum of H. pylori-related disease. It is, for example, crucial to demonstrate that this approach is as accurate among those who have had an upper gastrointestinal bleed or a peptic ulcer-a group in whom it is absolutely essential to demonstrate true eradication of H. pylori if one is to eliminate risk of re-bleeding.
You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content