why use 13c urea breath test for detecting Helicobacter pylori?
The urea breath test (UBT) is one of the most important non-invasive methods for detecting Helicobacter pylori infection. The test exploits the hydrolysis of orally administered urea by the enzyme urease, which H pylori produces in large quantities. Urea is hydrolysed to ammonia and carbon dioxide, which diffuses into the blood and is excreted by the lungs. Isotopically labelled CO2can be detected in breath using various methods.
Labelling urea with 13C is becoming increasingly popular because this non-radioactive isotope is innocuous and can be safely used in children and women of childbearing age.
Breath samples can also be sent by post or courier to remote analysis centres. The test is easy to perform and can be repeated as often as required in the same patient. A meal must be given to increase the contact time between the tracer and the H pylori urease inside the stomach. The test has been simplified to the point that two breath samples collected before and 30 minutes after the ingestion of urea in a liquid form suffice to provide reliable diagnostic information. The cost of producing 13C-urea is high, but it may be possible to reduce the dosage further by administering it in capsule form.