14c Urea (Oral)

Peptic ulcers, believed to be affecting more than half of the world's population, occurs when the bacterium Helicobacter pylori inhabits your stomach. 14C Urea is a radiopharmaceutical agent administered orally to detect stomach ulcers causing bacterium.


Helicobacter pylori (also known as H. pylori) is a type of bacteria that lives in the gut. It causes most forms of stomach ulcers such as sores in the stomach and intestinal lining. However, not everyone who has this bacterium in their gut develops stomach ulcers.

The presence of Helicobacter pylori in the stomach is diagnosed using 14 C Urea, a radiopharmaceutical agent that is taken by mouth. 14C Urea is basically urea attached to carbon 14 atom. H. pylori breaks down urea to release radioactive carbon dioxide gas, which is eventually exhaled in the breath. The level of radioactive carbon dioxide is then measured to see whether the patient has the bacteria in the gut.

14 C Urea is a radioactive agent. However, the amount used for this test is negligible, thus the amount of radiation received by the body is very low and considered safe. That said, the agent should only be administered by or under close supervision of a healthcare provider with specialized training in nuclear medicine.

The Urea 14 C breath test is a non-invasive technique used to detect the presence of H. pylori in the gut before and after treatment. The technique is rapidly growing in popularity for identifying infections caused by Helicobacter pylori in the gut. The bacterium is known to cause ulcers, inflammation and atrophy of the stomach. Left untreated, H. pylori infection will eventually irritate and destroy the lining of the stomach. The bacterium is also a risk factor for diseases like gastric cancer as well as the onset of malignant stomach lymphoma.

Conducting the urea breath test, as it is commonly referred to, is fairly simple. The patient is required to swallow a capsule containing 14 C urea. The urea breaks down into carbon dioxide gas. The carbon dioxide is then absorbed into the blood stream where it travels to the lungs for elimination from the body via breath. The breath sample is then collected and the levels of exhaled carbon measured. A base-line breath sample and a 15-minute post-urea 14 C dose sample are collected into breath bags for this test. Breath samples are tested to determine whether they contain material formed when the bacterium comes into contact with the radioactive urea. This test usually takes about 1 hour 30 minutes. A positive result means that H. pylori is present in the patient's gut. The degree of infection is established after comparing the measurements between pre and post urea testing. In case of an infection, H. pylori can be effectively treated using antibiotics.

There are basically two types of urea breath tests for detecting the presence of H. pylori bacteria in the gut. The first test involves use of a very small dose of urea labeled with a radioactive carbon isotope while the other uses urea labeled with non-radioactive carbon isotope. The non-radioactive carbon isotope test presents no significant side effects.

14 C Urea should be administered 14 days after the patient stops acid reducing medication, or four weeks after stopping all forms of antibiotic treatments. Also, the patient should not eat for at least six hours before taking the test.

Point to note

While this test is a painless diagnostic procedure, it is important to acknowledge that it is highly sensitive as it tests the entire gastric mucosa for presence of H. pylori infections.

Conditions treated

Type of medicine

  • Diagnostic aid (Helicobacter pylori infection)

Side Effects

There are no major side effects of 14 C urea. However, some healthcare providers do not approve Phenylketonuric patients for this test as some urea breath side effects might affect them.

One way to minimize possible risks of 14 C urea test false results is to ensure the accurate reading of results. Thus, it is important that the patient goes without food for at least six hours before the test. Some prescription medications such as H2 blockers, antibiotics and proton pump inhibitors should also be avoided days leading up to the test.

Some patients may experience allergic reactions such as hives or itching, swelling on the face or limbs, chest tightness, difficulty in breathing and tingling in the mouth and throat after taking this test.


Oral dosage for adults and adolescents

Your healthcare provider will give you a capsule to swallow with lukewarm water. Swallow the capsule whole. Do not chew it. Never touch the capsule with bare hands as this might cause incorrect test results.

0.037 megabecquerel ( 1-microcurie) followed by a collection of breath sample after 10 minutes. The sample should be read repeatedly until values 10 minutes apart are similar.

The results are interpreted as follows:

  • Less than 50 DPM (disintegrations per minute) - Negative for H. pylori
  • 50 to 199 DPM - intermediate for H. pylori
  • 200 DPM and more - positive for H. pylori


Risk from radiation is quite negligible. However, in an event of overdose, the patient should drink as much water as possible to speed up the isotope's elimination from the body. Call the Poison and Control Center for information on overdose or unintentional ingestion management.


Consult your doctor before using any medication, including over-the-counter prescriptions, supplements, and herbal products alongside 14 C urea.

Do not use antibiotics (medicines used to treat infections) or drugs that contain bismuth (such as Pepto-Bismol) four weeks before this test. Also, avoid sucralfate (brand name Carafate), lansoprazole (brand name Prevacid), and omeprazole (brand name Prilosec) two weeks leading up to this test. These medications may interfere with test results. Inform your healthcare provider before the test if you have used any of these drugs in recent weeks.


In deciding to take this test, any risks of the test should be weighed against potential benefits. This is a decision you should make after adequate consultation with your doctor. Also, the result may be affected by other factors.

  • Talk to your doctor before taking this test if you are pregnant or breastfeeding
    14 C Urea capsules contain very small amounts of radioactivity. However, consider talking to your doctor about any concerns you might have concerning this product.
  • Tell your healthcare provider if you have ever had allergic or unusual reactions to this or other medications. Also, remember to tell your doctor if you have any other forms of allergies such as dyes, foods, preservatives and animals.
  • The amount of radiation in 14 C Urea is very low and considered safe for children. However, be sure to discuss with your doctor the risks versus the benefits of exposing your young one to radiation.
  • Repeated use of 14 C Urea may also trigger other medical problems, especially achlorhydria as a result of resective gastric surgery.


14 C Urea capsules and kit should be stored at 59-86 degree F (15-30 degrees C). Store the kit in a dry place away from direct sunlight. Keep out of the reach of children and pets. All expired or unused medication should be disposed of appropriately.


14 C Urea is a radiopharmaceutical used to detect the presence of stomach ulcers causing bacterium known as Helicobacter pylori in the gut. The agent is taken orally. If the patient has the bacteria in their gut, the agent is broken down into radioactive carbon dioxide gas. This gas is then expelled from the body through breath. The levels of radioactive carbon dioxide gas in the breath is then measured to determine whether the patient has Helicobacter pylori in their stomach.

14 C Urea is radioactive. However, with negligible amounts in the capsule that is used to perform the test, the levels of radiation the body receives is quite low and considered safe. That said, 14 C Urea should only be administered under direct supervision of a healthcare provider with specialized training in nuclear medicine.

14 C Urea test results can be affected by a number of conditions, especially the patient's sensitivity to urea. Medications like bismuth-containing solutions, antibiotics, proton pump inhibitors and sucralfate can also affect the efficiency of the test.

Talk to your doctor if you are using any of these medications:

  • Do not take anything for at least six hours before taking this test.
  • The test should only be administered by your healthcare provider. The person administering the test will give you a capsule, which you must not touch with bare fingers, to swallow with a small amount of lukewarm water.
  • Swallow the capsule without chewing or breaking it.
  • 3-5 minutes after swallowing the capsule, you will need to drink another small amount of water to drive the capsule down into your stomach.
  • 10 minutes after taking the sample, you will give the first sample of breath by blowing through a straw connected to a balloon.
  • Multiple samples will be taken and carbon dioxide levels measured against a baseline.
Last Reviewed:
January 30, 2018
Last Updated:
April 04, 2018
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