Who Needs RUT Testing During Endoscopy
Rapid urease testing (RUT) should be performed during endoscopy in all patients undergoing upper endoscopy for dyspeptic symptoms, peptic ulcer disease, or gastritis to guide H. pylori eradication therapy, with the critical exception that RUT alone is insufficient in patients with active GI bleeding, where additional biopsies for histology must be obtained due to significantly reduced test sensitivity. 1, 2, 3
Primary Indications for RUT During Endoscopy
Patients Who Should Receive RUT Testing
All patients over age 45 with new or changed dyspeptic symptoms undergoing endoscopy require RUT testing, as this population needs both cancer exclusion and H. pylori diagnosis 1
Patients under 45 with dyspepsia and risk factors including NSAID use or those who test positive on non-invasive H. pylori testing should have RUT performed if endoscopy is indicated 1
Any patient found to have peptic ulcer disease (gastric or duodenal ulcer) at endoscopy requires RUT testing, as over 95% of duodenal ulcers and most gastric ulcers are H. pylori-related, and eradication leads to long-term cure 1
Patients with gastritis or erosive changes identified during endoscopy should undergo RUT to determine if H. pylori eradication therapy is indicated 4, 5
Patients requiring long-term acid suppression therapy (PPIs or H2 blockers) should have H. pylori status determined via RUT during endoscopy 1
Critical Situations Requiring Modified RUT Approach
Active GI Bleeding: RUT Has Unacceptably Low Sensitivity
In patients with bleeding peptic ulcers, RUT sensitivity drops dramatically to 54-76% with a false-negative rate of 25%, compared to 80-95% sensitivity in non-bleeding patients 2, 3, 6
Additional biopsies for histology are mandatory when RUT is performed in bleeding patients, as histology maintains 89% sensitivity even during active bleeding 2
If RUT is positive in a bleeding patient, the result is reliable (specificity remains 100%), but a negative result cannot exclude H. pylori infection 2, 3
Optimizing RUT Accuracy During Endoscopy
Obtain biopsies from both antrum AND gastric body rather than antrum alone, as this improves sensitivity from 61% to 73-74% in bleeding patients and accounts for bacterial migration in patients on acid suppression 7, 6
Take multiple biopsies (4 pieces) from the antrum if only sampling one location, as this significantly increases sensitivity compared to single biopsy (74% vs 61%) 7
Ensure patients have discontinued PPIs, antibiotics, and bismuth for at least 2 weeks before endoscopy when possible, as these medications reduce bacterial load and cause false-negative results 1, 8
Patients Who Do NOT Need RUT During Endoscopy
Patients with typical irritable bowel syndrome symptoms rather than true dyspepsia should not undergo endoscopy or RUT testing 1
Patients with mild reflux symptoms responding to simple measures do not require endoscopy or RUT 1
Patients with known duodenal ulcer already responding to treatment do not need repeat endoscopy or RUT 1
Asymptomatic patients or those who had a single self-limited episode of dyspepsia do not require endoscopy or RUT 1
Important Clinical Pitfalls
Never rely solely on RUT in patients over 45 years, as endoscopy is required to exclude gastric cancer regardless of H. pylori status, and RUT should be performed as an adjunct test 1, 8
Do not use RUT results alone to confirm eradication after treatment; non-invasive testing (urea breath test or stool antigen) at least 4 weeks post-treatment is required 1, 5
False-positive RUTs can occur in achlorhydria due to non-H. pylori urease-producing organisms, particularly in patients with pernicious anemia or atrophic gastritis 1
Reading RUT at 1 hour is as accurate as 24-hour reading with newer ultra-rapid formulations, providing immediate results during the endoscopy visit 9