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Urea Breath Test

Bacterial infections Biomarker

Sample Needed

Collection Type: Blood

Body System

Related System: Bacterial infections

Overview

The urea breath test (UBT) detects active infection with Helicobacter pylori by measuring labeled carbon dioxide in the breath after ingestion of labeled urea. H. pylori produces urease, which splits urea into ammonia and labeled CO2; increased labeled CO2 in exhaled breath indicates gastric H. pylori urease activity. The test is used when peptic ulcer disease, dyspepsia, unexplained iron-deficiency anemia, or gastric MALT lymphoma is suspected, or to confirm eradication after therapy. Accuracy is high in adults and children (with dose adjustments); results can be affected by recent antibiotics, proton-pump inhibitors, bismuth, recent upper GI bleeding, or prior gastric surgery rather than by age or sex alone.

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Test Preparation

No food or drink for at least 4 hours prior

Why Do I Need This Test

Profile: Bacterial infections (H.
pylori detection and post-treatment check).
Symptoms suggesting test: chronic/relapsing dyspepsia, epigastric pain, bloating, nausea, GI bleeding, unexplained iron deficiency.
Diagnoses/monitoring: active H.
pylori infection; test-of-cure after eradication therapy.
Reasons for abnormal: true infection (positive) or suppressed bacteria/medication interference (false negative); non-H.
pylori urease-producing organisms (rare false positive).
Biological meaning: positive = active gastric colonization producing urease.
Behaviors: recent antibiotics, PPIs, bismuth, or smoking can alter results.
Family history: family members with peptic ulcer disease or known H.
pylori may increase pretest suspicion.

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Understanding Test Results

For the commonly used 13C-UBT, a delta (increase over baseline) <4.0 is considered negative (no active H.
pylori).
A delta ≥4.0 is positive and indicates active H.
pylori infection.
Values between roughly 2.5–4.0 may be indeterminate and warrant repeat testing or alternative testing.
For 14C-UBT, counts <50 cpm (or dpm depending on lab reporting) are negative; counts ≥50 cpm are typically positive.
False negatives occur if the patient recently took antibiotics or bismuth (stop ≥4 weeks) or proton-pump inhibitors (stop ≥2 weeks) before testing, or after recent GI bleeding or partial gastrectomy.
False positives are uncommon but may arise from non-H.
pylori urease-producing organisms or laboratory/collection error.
A positive result should prompt treatment and, after therapy, repeat testing (using UBT) at least 4 weeks after antibiotics/bismuth and ≥2 weeks after stopping PPIs to confirm eradication.

Normal Range

<4.0 (delta13C) OR <50 cpm (14C)

FAQs

Q: What is a urea breath test?

A: A urea breath test detects Helicobacter pylori infection in the stomach. After fasting, you swallow a capsule or drink containing labeled urea; if H. pylori is present, its urease breaks urea into labeled carbon dioxide, which appears in your exhaled breath and is measured. The test is noninvasive, accurate for diagnosis and confirming eradication; antibiotics or proton pump inhibitors should be stopped beforehand.

Q: What if urea breath test is positive?

A: If your urea breath test is positive, it means you likely have Helicobacter pylori infection. Your doctor will usually prescribe eradication therapy: a proton‑pump inhibitor plus two antibiotics, and may tailor treatment for resistance. After therapy you'll need a follow‑up breath or stool test (typically 4 or more weeks after antibiotics) to confirm cure. Untreated infection can cause ulcers and raise gastric cancer risk.

Q: What are the first symptoms of H. pylori?

A: Many people with H. pylori have no early symptoms. When present, first signs typically include a burning or gnawing pain or discomfort in the upper abdomen (especially when the stomach is empty), bloating, frequent belching, nausea, early feeling of fullness, and loss of appetite. Some may also experience intermittent heartburn or unexplained weight loss. Seek medical testing for persistent symptoms.

Q: How to prepare for an urea breath test?

A: Before a urea breath test: stop antibiotics and bismuth for 4 weeks and proton‑pump inhibitors for 2 weeks (confirm with your clinician before stopping meds). Avoid H2 blockers for 24 hours. Fast no food or drink for about 6 hours before the test. Don’t smoke, chew gum, or brush teeth immediately beforehand. Bring a medication list and tell staff if pregnant, breastfeeding, or unwell.

Q: Is a urea breath test safe?

A: A urea breath test is a noninvasive, generally safe procedure for detecting H. pylori. You swallow urea labeled with carbon-13 (nonradioactive) or low-dose carbon-14; side effects are rare. Inform your clinician if pregnant, breastfeeding, or on antibiotics/proton-pump inhibitors, as these affect test choice or accuracy. Discuss alternatives (stool antigen) if there are pregnancy concerns.

Q: Can you treat H. pylori naturally?

A: You generally cannot reliably eradicate H. pylori with natural remedies alone. Standard care is doctor-prescribed antibiotics plus a proton‑pump inhibitor; probiotics, some herbal agents (e.g., mastic, berberine) and dietary changes may relieve symptoms or support treatment but aren’t proven to replace antibiotics. Get tested and follow physician-directed therapy to prevent complications.