14C - Urea Breath Test

14C-Urea Breath Test (14C-UBT) – A Non-Invasive Method for Detecting Helicobacter pylori Infection

The 14C-urea breath test (14C-UBT) is a widely used, non-invasive diagnostic method for detecting Helicobacter pylori infection, known for its high accuracy and convenience. Below is a detailed introduction:

1. Test Principle

✅ pylori produces urease, an enzyme that breaks down urea into ammonia and carbon dioxide (CO₂). After the patient ingests a capsule containing 14C-labeled urea:

✅If infected: Bacterial urease decomposes urea, releasing 14C-labeled CO₂, which enters the bloodstream and is exhaled.

✅If not infected: The urea remains undigested, and no 14C-labeled CO₂ is detected in the breath.

✅The test measures the radioactive activity of 14C in the exhaled breath to determine infection status.

2. Test Procedure

✅Fasting preparation: The patient must fast (typically for at least 4 hours).

✅Capsule ingestion: The patient swallows the 14C-urea capsule and waits quietly for 15–30 minutes.

✅Breath collection: The patient exhales into a specialized collection card or liquid to capture CO₂.

✅Instrument analysis: A liquid scintillation counter or mass spectrometer measures the 14C content.

3. Advantages

✅High accuracy: Sensitivity and specificity both exceed 95%, making it an internationally recognized "gold standard."

✅Non-invasive and convenient: No endoscopy required, suitable for children, elderly, and others who cannot tolerate invasive procedures.

✅Rapid results: Reports are typically available within 30 minutes.

✅Wide applicability: Used for initial diagnosis and post-treatment evaluation (e.g., after eradication therapy).

4. Precautions

✅Caution for pregnant and breastfeeding women: Due to minimal radioactivity (though the dose is extremely low, equivalent to 1–2 days of natural background radiation).

✅Medication interference: Discontinue antibiotics, bismuth preparations (2–4 weeks), and proton pump inhibitors (PPIs, 1–2 weeks) before testing to avoid false negatives.

✅Dietary requirements: Avoid alcohol and high-protein meals before the test; fasting ensures more accurate results.

5. Radiation Safety

✅Minimal dose: 14C emits weak beta radiation; a single test exposes the patient to ~0.001–0.003 mSv (less than daily natural background exposure), posing no harm.

✅Rapid excretion: Undigested 14C-urea is excreted in urine within 48 hours.

6. Target Population

✅Individuals with symptoms like indigestion or stomach pain suspected of H. pylori infection.

✅Those with a family history of gastric cancer or long-term NSAID users.

✅Post-treatment efficacy assessment (recommended 4 weeks after stopping medication).

Summary

The 14C-UBT is an efficient, accurate, and safe method for diagnosing H. pylori infection. While it involves trace radioactivity, the risk is negligible. Patients should follow pre-test medication adjustments for reliable results. For those concerned about radiation, the non-radioactive 13C-urea breath test is an alternative, though at a higher cost.