H. pylori testing: All methods are not created equal

Figure 1. In the United States, approximately 40% of individuals are seropositive for H. pylori antibodies.⁶

Test-Treat-Test strategy for H. pylori infection

H. pylori antibiotic resistance is on the rise, and rates of eradication are declining. A recent review of
H. pylori strain resistance patterns in the United States indicates resistance rates of 30-42% for clarithromycin, levofloxacin, and metronidazole.²

As a result, the American College of Gastroenterology (ACG), the American Gastroenterological Association (AGA), the Houston Consensus Conference, and the World Gastroenterology Organisation (WGO) recommend a “test-treat-test” strategy with stool antigen test or urea breath test (UBT) used to diagnose current H. pylori infection and to confirm eradication after treatment. SAT and UBT are non-invasive testing methods that offer excellent sensitivity and specificity for initial diagnosis of H. pylori infection and posttreatment testing.³

Figure 2. Approximately 20% of H. pylori seropositive and symptomatic individuals are negative for stool antigen. The other 80% of seropositive and symptomatic individuals, stool antigen positive results indicate current H. pylori infection.⁶

What about H. pylori serology testing?

H. pylori antibodies are often detectable by serological evaluation for many years following infection resolution. Since antibody presence is not specific for a current H. pylori infection, serology testing is no longer used as a diagnostic tool in many laboratories. In addition, an increasing number of health insurance providers indicate that serologic testing is “not medically necessary” and no longer reimburse for H. pylori serology testing.⁴ In a review article published in the New England Journal of Medicine, serology testing was not included as an acceptable testing method for H. pylori infection diagnosis.⁵

The American Academy of Family Physicians (AAFP) and the American Society for Clinical Pathology (ASCP) do not consider serology testing for H. pylori to be clinically useful and do not support using serology for H. pylori testing. Currently, AAFP and ASCP recommend alternative noninvasive testing methods, such as the stool antigen test or UBT, to diagnose H. pylori infection and for eradication confirmation. These tests offer superior sensitivity and specificity when compared to serology, detecting the presence of H. pylori bacteria instead of antibodies to H. pylori.