From the Guidelines
When a urease breath test result is reported as equivocal, the best approach is to repeat the test after ensuring optimal testing conditions or consider an alternative diagnostic method for H. pylori. Before repeating the test, patients should discontinue proton pump inhibitors (PPIs) for at least 2 weeks, antibiotics for 4 weeks, and bismuth preparations for 2 weeks, as these can cause false-negative results 1. Patients should also fast for at least 6 hours before the test and avoid smoking on the test day. If the repeat test remains equivocal, alternative diagnostic methods include stool antigen testing, serological testing for H. pylori antibodies, or endoscopy with biopsy for histology and culture. Equivocal results often occur due to recent medication use, improper test administration, or a low bacterial load that produces borderline urease activity. In clinical practice, if there is a strong suspicion of H. pylori infection despite equivocal test results, especially in high-risk patients or those with persistent symptoms, empiric treatment with standard H. pylori eradication therapy may be considered, followed by confirmation of eradication at least 4 weeks after completion of therapy 1. Some key points to consider when interpreting urease breath test results include:
- The sensitivity and specificity of the UBT are in the range of 97% and 95%, respectively 1.
- Recent use of antibiotics or proton pump inhibitors can lead to false-negative results in up to 40% of patients 1.
- Giving citrate before and at the time of 14C urea administration may increase mean breath 14CO2 excretion and decrease false-negative and equivocal UBT results in patients taking proton pump inhibitors 1. However, the most recent and highest quality study 1 provides the best guidance for clinical practice.
From the Research
Urease Breath Test Results Reported as Equivocal
When a urease breath test result is reported as equivocal, it means that the test results are not clearly positive or negative. This can be due to various factors, including:
- Interference from proton pump inhibitors (PPIs) or other medications 2, 3, 4, 5
- Recent use of antibiotics or bismuth preparations 6
- Inadequate test protocol or sample collection 6
Possible Causes of Equivocal Results
Some studies have investigated the effects of PPIs on urease breath test results:
- Omeprazole and lansoprazole have been shown to cause false negative results in some patients 3, 4, 5
- Pantoprazole has been found to have a lower risk of causing false negative results compared to other PPIs 4, 5
- The use of acidified 14C-urea capsule did not prevent false negative UBT results in patients taking pantoprazole and ranitidine 2
Next Steps
If a urease breath test result is reported as equivocal, the following steps can be taken:
- Repeat the test after a certain period of time (e.g., 2 weeks) to allow for any interfering medications to be cleared from the system 3, 6
- Use a different test protocol or sample collection method to minimize interference from medications or other factors 6
- Consider using a different diagnostic test, such as endoscopy or stool antigen test, to confirm the presence of H. pylori infection 6