Non-endoscopic tests in the diagnosis of Helicobacter pylori infection.

The urea breath test (UBT) and serological antibody detection are simpler and less expensive than endoscopic tests for the diagnosis of Helicobacter pylori. For the UBT, either non-radioactive 13C or radioactive 14C is used as an isotopic marker. 14C-UBTs are cheaper and are safe, but licensing regulations may make them inconvenient. Some UBTs have been simplified by omitting the normal test meal and encapsulating the urea to avoid metabolism by oral bacteria. These modified test need further validation, especially when used for assessing H. pylori status after treatment. Serological tests detect circulating IgG or IgA. They are of variable accuracy, the best performing as well as UBTs. Paired serum samples pre-treatment and 6 months post-treatment accurately assess treatment success. Rapid in-office tests appear less accurate and cannot be used for post-treatment assessment. In practice, for primary diagnosis of H. pylori infection, endoscopic tests are best because endoscopy allows assessment of treatment indications. Where indications already exist or taking biopsies is dangerous. UBTs or serology are suitable, but serology is cheaper and more convenient. After treatment, endoscopy is usually unnecessary and UBTs accurately assess H. pylori status at 4 weeks. Serology is an alternative only if results are not required before 6 months.