urea breath test(redirected from PY test)
urea breath testA rapid diagnostic test used to identify Helicobacter pylori, based upon its ability to convert urea to ammonia. Formerly considered the gold standard non-invasive test for H pylori, the urea breath test is being replaced by the monoclonal stool antigen test, which is more sensitive (97%) and more specific (96%).
urea breath testGI disease A noninvasive test for the presence of H pylori in the stomach, based on H pylori's urease activity. See Helicobacter pylori.
Urea Breath Test
Synonym/acronym: PY test, C-14 urea breath test, breath test, pylori breath test, UBT.
To assist in diagnosing a gastrointestinal infection and ulceration of the stomach or duodenum related to a Helicobacter pylori infection.
Area of applicationStomach.
ContrastRadioactive C-14 urea in capsule form.
The C-14 urea breath test (UBT) is used to assist in the diagnosis of Helicobacter pylori infection. H. pylori is a bacteria that can infect the stomach lining. It has been implicated as the cause of many gastrointestinal conditions, including the development of duodenal and gastric ulcers. The UBT is a simple, noninvasive diagnostic nuclear medicine procedure that requires the patient to swallow a small amount of radiopharmaceutical C-14–labeled urea in a capsule with lukewarm water. In the presence of urease, an enzyme secreted by H. pylori in the gut, the urea in the capsule is broken down into nitrogen and C-14–labeled carbon dioxide (CO2). The labeled CO2 is absorbed through the stomach lining into the blood and excreted by the lungs. Breath samples are collected and trapped in a Mylar balloon. The C-14 urea is counted and quantitated with a liquid scintillation counter. The UBT can also be used to indicate the elimination of H. pylori infection after treatment with antibiotics. Other tests used to detect the presence of H. pylori include a blood H. pylori antibody test, a stool antigen test, and stomach biopsy.
This procedure is contraindicated for
- Patients who are pregnant or suspected of being pregnant, unless the potential benefits of a procedure using radiation far outweigh the risk of radiation exposure to the fetus and mother.
- Patients who have taken antibiotics, Pepto-Bismol, or bismuth in the past 30 days.
- Patients who have taken sucralfate in the past 14 days.
- Patients who have used a proton pump inhibitor within the past 14 days.
- Aid in detection of H. pylori infection in the stomach
- Monitor eradication of H. pylori infection following treatment regimen
- Evaluate new-onset dyspepsia
- Negative for H. pylori: Less than 50 dpm (disintegrations per minute)
Abnormal findings related to
- Indeterminate for H. pylori: 50 to 199 dpm
- Positive for H. pylori: Greater than 200 dpm
- Consultation with a health-care provider (HCP) should occur before the procedure for radiation safety concerns regarding younger patients or patients who are lactating. Pediatric & Geriatric Imaging Children and geriatric patients are at risk for receiving a higher radiation dose than necessary if settings are not adjusted for their small size. Pediatric Imaging Information on the Image Gently Campaign can be found at the Alliance for Radiation Safety in Pediatric Imaging (www.pedrad.org/associations/5364/ig/).
- Failure to follow dietary restrictions and other pretesting preparations may cause the procedure to be canceled or repeated.
- Patients who have had resective gastric surgery have the potential for resultant bacterial overgrowth (non-H. pylori urease), which can cause a false-positive result.
- Achlorhydria can cause a false-positive result.
Nursing Implications and Procedure
- Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
- Patient Teaching: Inform the patient this procedure can assist in diagnosing an infection of the stomach or intestine.
- Obtain a history of the patient’s gastrointestinal system, symptoms, and results of previously performed laboratory tests and diagnostic and surgical procedures.
- Record the date of the last menstrual period and determine the possibility of pregnancy in premenopausal women.
- Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values online at DavisPlus).
- Review the procedure with the patient. Reassure the patient that the radionuclide poses no radioactive hazard and rarely produces side effects. Address concerns about pain and explain that there should be no discomfort during the procedure. Inform the patient that the procedure is done in the nuclear medicine department by technologists and support staff and usually takes approximately 30 to 60 min.
- Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
- Instruct the patient to fast, restrict fluids, and, by medical direction, withhold medication for 6 hr prior to the procedure. Protocols may vary among facilities.
- Potential complications: N/A
- Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient.
- Ensure the patient has complied with dietary and medication restrictions and pretesting preparations; assure that food, fluids, and medications have been restricted for at least 6 hr prior to the procedure.
- Instruct the patient to blow into a balloon prior to the start of the procedure to collect a sample of breath.
- Instruct the patient to swallow the C-14 capsule directly from a cup, followed by 20 mL of lukewarm water. Provide an additional 20 mL of lukewarm water for the patient to drink at 3 min after the dose.
- Take breath samples at different periods of time by instructing the patient to take in a deep breath and hold it for approximately 5 to 10 sec before exhaling through a straw into a Mylar balloon.
- Note that samples are counted on a liquid scintillation counter (LSC) and recorded in disintegrations per minute.
- Inform the patient that a report of the results will be made available to the requesting HCP, who will discuss the results with the patient.
- Instruct the patient to resume usual diet and medication, as directed by the HCP.
- Unless contraindicated, advise patient to drink increased amounts of fluids for 12 to 24 hr to eliminate the radionuclide from the body.
- If a woman who is breastfeeding must have a breath test, she should not breastfeed the infant until the radionuclide has been eliminated. She should be instructed to express the milk and discard it during a 3-day period to prevent cessation of milk production.
- Recognize anxiety related to test results. Discuss the implications of abnormal test results on the patient’s lifestyle. Provide teaching and information regarding the clinical implications of the test results, as appropriate.
- Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP. Answer any questions or address any concerns voiced by the patient or family.
- Depending on the results of the procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.
- Related tests include EGD, gastric emptying scan, H. pylori antibody, KUB study, and UGI.
- See the Gastrointestinal System table at the end of the book for related tests by body system.