Accuracy of IgG serology and other tests in confirming Helicobacter pylori eradication.

BACKGROUND

In this study we assessed the accuracy of IgG serology and other tests in confirming Helicobacter pylori eradication.

METHODS

The outcome of anti-H. pylori therapy was established by at least two of the following tests: rapid urease test (RUT), culture, 14C urea breath test (non-capsule or capsule UBT), and IgG serology (Orion Diagnostica Pyloriset New EIA-G).

RESULTS

Successful H. pylori eradication was confirmed in 698 of 794 patients (88%). The percentage decrease in IgG antibody titre was related to the patients' pre-treatment IgG titre and time interval after treatment. A decrease in IgG titres of 40% or more confirmed H. pylori eradication with 100% specificity, whereas the sensitivity was 82%, 90%, 98%, and 98% 3, 4, 5, and 6 months after therapy, respectively. The 40% cut-off confirmed eradication 3 to 6 months after therapy in 328 of 339 patients (97%) with pre-treatment IgG titres of >700, in 36 of 45 patients (80%) with pre-treatment titres of 300-700, and in 5 of 12 patients (42%) with pretreatment titres of <300. The sensitivity and specificity of the other tests 2 months after treatment were as follows: RUT, 84% and 100%; culture, 88% and 100%; non-capsule UBT, 100% and 89%; and capsule UBT, 100% and 97%.

CONCLUSION

A decrease in IgG antibody titre of 40% or more 3 to 6 months after therapy and the capsule 14C UBT at the 2-month follow-up were both highly accurate in confirming H. pylori eradication.