Norm of Urea Breath Test (UBT, 13C-UBT, 14C-UBT)
Negative for Helicobacter pylori.
Usage of Urea Breath Test (UBT, 13C-UBT, 14C-UBT)
Diagnosis of gastric H. pylori colonization. This test is useful in children and adults and is a sensitive indicator of H. pylori eradication 4–6 weeks after treatment with antibiotics. Considered the test of choice to confirm H. pylori infection.
Description of Urea Breath Test (UBT, 13C-UBT, 14C-UBT)
H. pylori infection is an underlying cause found in most cases of gastritis and duodenal ulcer/peptic ulcer. In addition, H. pylori is a carcinogen that causes gastric cancer and is also associated with stroke, coronary artery disease, and vitamin B12 deficiency. H. pylori infection is thought to be acquired in childhood, with the highest rates of seroconversion occurring in those ages 4–5 years. This organism is the most common type of bacterial pathogen, in that it is colonized in more than half of adults >40 years. The source of infection is thought to be direct person-to-person transmission, but isolates have inconsistently been found in water, food, or animals.
The urea breath test detects exhaled labeled carbon dioxide absorbed into the bloodstream from the stomach when the urease enzyme produced by H. pylori degrades ingested radiolabeled urea. The labeled carbon dioxide (CO2), known as 13C or 14C, is present in exhalations within 10–30 minutes. After the radiolabeled urea is ingested, a test meal is given to delay emptying from the stomach so as to allow the urease enzyme to act. The addition of citric acid to the test meal improves the sensitivity and specificity of the urea breath test. The difference between the 13C and 14C tests is that the 14C is radioactive, is inexpensive, and can be interpreted using a liquid scintillation counter, widely available in radiology settings. The 13C test is not radioactive and may be performed in any setting, but is much more expensive, and the mass spectrometer equipment needed for interpretation is not widely available
Professional Considerations of Urea Breath Test (UBT, 13C-UBT, 14C-UBT)
Consent form NOT required for the 13C test. Consent form IS required for the 14C test.
There is a very small amount of radiation with the 14C test.
The 14C test is contraindicated during pregnancy.
- Obtain 200 mL of test drink for client ingestion.
- Remove dentures, if present, to avoid trapping of the mixture under them.
- See Client and Family Teaching.
- Just before beginning the procedure, take a “time out” to verify the correct client, procedure, and site.
- 14C test:
- a. The client must rinse his/her mouth before drinking the mixture.
- b. A baseline breath is taken by having the client blow into a solution that contains an acid/base indicator.
- c. The client drinks a mixture or ingests a pill of radiolabeled 14C-urea. A standard meal may be given.
- d. Breath samples are measured at frequent intervals (e.g., 6, 12, 20, and 30 minutes) after ingestion.
- e. Alternatively, the client will blow into a balloon 10 minutes after urea ingestion and the balloon contents are transferred to a trapping solution for analysis.
- 13C test:
- a. The client drinks a mixture of radiolabeled 13C-urea or 14C-urea. A standard meal may be given.
- b. Breath samples are taken by being blown into a bag or balloon.
- c. In the 13C test, breath samples are measured at 0 and at 30 minutes after ingestion of the urea mixture.
- The client may resume eating and drinking and all medications.
Client and Family Teaching
- Do not take antibiotics (except vancomycin, nalidixic acid, trimethoprim, amphotericin B) or bismuth mixtures (e.g., Pepto-Bismol) within 1 month before the test.
- Do not take omeprazole, lansoprazole, or pantoprazole within 14 days before the test.
- Do not take cimetidine, famotidine, nizatidine, or ranitidine within 24 hours before the test.
- Do NOT eat or drink for at least 6 hours before the test.
- The test takes about 30 minutes.
- 13C test only: There is no radioactivity exposure from this test.
- 14C test only: The radioactivity received from this test is much less than that received from a regular chest radiograph and less than what you normally receive from a natural day of radiation.
Factors That Affect Results
- A fatty meal profoundly affects results by increasing values at 30-, 40-, 50-, 60-, 90-, and 120-minute intervals.
- Taking antibiotics or Pepto-Bismol for 1 month or Prilosec or Carafate for 1 week before the test can cause false-negative results.
- Taking drugs that inhibit bacterial growth, such as antibiotics, within 1 month before the test can cause false-negative results.
- Antacids may produce falsely low results.
- Substituting orange juice for citric acid reduces diagnostic accuracy (specificity) of this test. Citric acid has 100% specificity, but orange juice has only 88% specificity.
- H. pylori infection is treated with a 7-day cycle of tetracycline, metronidazole, and bismuth subsalicylate.
- See also Campylobacter-like organism test—Specimen ; Helicobacter pylori, Quick office serology, Serum and titer—Blood.