urea breath test

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urea breath test

A 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 test

GI 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.

Common use

To assist in diagnosing a gastrointestinal infection and ulceration of the stomach or duodenum related to a Helicobacter pylori infection.

Area of application

Stomach.

Contrast

Radioactive C-14 urea in capsule form.

Description

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

  • high alert 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.
  • high alert Patients who have taken antibiotics, Pepto-Bismol, or bismuth in the past 30 days.
  • high alert Patients who have taken sucralfate in the past 14 days.
  • high alert Patients who have used a proton pump inhibitor within the past 14 days.

Indications

  • Aid in detection of H. pylori infection in the stomach
  • Monitor eradication of H. pylori infection following treatment regimen
  • Evaluate new-onset dyspepsia

Potential diagnosis

Normal findings

  • 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

Critical findings

    N/A

Interfering factors

  • Other considerations

    • 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

Pretest

  • 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.

Intratest

  • 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.

Post-Test

  • 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 Monographs

  • 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.

test

trial/experiment assisting diagnosis
  • Allen's test test of arterial occlusion in the foot, i.e. leg elevation (until plantar skin blanches and Doppler sound at dorsalis pedis [DP] pulse is lost) followed by compression of DP pulse (by clinician's thumb) and lowering of leg to dependency; if posterior tibial artery flow is adequate the foot rapidly resumes its normal colour; test is repeated at posterior tibial pulse, to test patency of DP

  • anterior drawer test; ADT; Lachman's test test of stability/integrity of lateral collateral ligaments of ankle joint, i.e. flex knee to >45° (to relax posterior muscle group), stabilize lower tibia (with one hand) whilst grasping posterior aspect of patient's heel (with the other); calcaneum is pulled forward as a simultaneous retrograde force is applied to lower tibia; positive ADT = > 4mm anterior displacement of foot relative to tibia together with positive 'suction sign'

  • Buerger's test test of arterial status of lower limb, i.e. patient reclines supine on couch; leg is elevated (from hip) for 1 minute (whilst patient alternately dorsi- and plantarflexes ankle joint, to drain venous circulation); limb is lowered to dependency or patient stands up (foot shows brief hyperaemia before returning to normal skin colour); time (in seconds) for normal colour return is noted; >20 seconds = inadequate arterial supply; >40 seconds = severe limb ischaemia; note: clinician should note whether cyanosis (rather than brief hyperaemia) occurs on dependency, and duration of cyanosis; persistent dusky red/purple coloration in dependent limb that appears to resolve to normal skin tone on raising limb to horizontal indicates severe arterial compromise

  • Clarke's test diagnostic test of chondromalcia patellae; with the patient supine and the affected knee fully extended, the clinician applies gentle pressure to the patella whilst the patient attempts to contract the quadriceps muscle group; the test is positive if severe patellar pain occurs

  • Coombs test test to predict donor and receiver blood compatibility, i.e. assay for presence/absence of specific antibodies on donor erythrocytes

  • coordination tests tests of cerebellar coordination of lower-limb motor function, i.e. heel-shin test; fingertip test

  • fingertip test test of cerebellar function, i.e. patient repeatedly attempts to place his/her fingertip on tip of assessor's moving finger; alternatively, patient attempts to put tip of his/her index finger alternately on his/her nose then on assessor's moving finger

  • glass test test for meningitis, i.e. test is positive when there is no blanching of a pruritic rash when it is pressed with a glass

  • glucose tolerance test; GTT diagnostic test of diabetes mellitus, and assessment of patients with fasting blood glucose levels just above normal range (i.e. 5.6-6.7 mmol/L), i.e. 75mg glucose is given (as a drink) after starving for 12-14 hours; its rate of blood clearance is monitored over the next 3 hours; in normal patients, there is an immediate and sharp rise in blood glucose which falls during subsequent 2 hours to normal glycaemic levels (i.e. 2.9-5.9 mmol/L); in diabetes/insulin resistance cases, blood glucose levels rise initially to a higher level and do not return to normal range within 2 hours

  • Heaf test test of immunity to tubercle bacillus (tuberculosis [TB]), i.e. subdermal injection of attenuated tuberculin toxin

  • heel-shin test test of cerebellar function, i.e. patient repeatedly places one heel on anterior aspect of other shin and slides heel down to dorsum of foot; inability to perform this test indicates cerebellar dysfunction and other conditions characterized by loss of motor coordination

  • interdigital test reduced blunt/sharp discrimination, paraesthesia, hyper-/hypoaesthesia of interdigital skin at toe cleft affected by neuritis/Morton's neuroma

  • Jack's test passive dorsiflexion of hallux at first metatarsophalangeal joint in weight-bearing foot

  • Kelikian push-up test intraoperative check of adequate surgical correction of lesser-toe deformity, i.e. elevation of head of relevant metatarsal with thumb pressure

  • Lachman's test see test, anterior drawer

  • Mantoux test, tuberculin test screening test for exposure to tuberculosis (TB); administration of an intradermal dose of tuberculosis antigen (tuberculin) to the skin of the forearm; a localised, small, firm inflammatory skin reaction developing within 2 days shows positive exposure to tuberculosis

  • Mulder's test diagnostic test for Morton's neuroma, i.e. simultaneous lateral compression across metatarsal heads + thumb pressure at affected plantar web space in a foot with symptoms of plantar digital neuritis (Morton's neuroma); positive result (i.e. induction of characteristic symptoms of a nerve entrapment pain, and examiner's awareness of a fluid thrill [or click] within the palpated tissue) indicates neuritis or neuroma

  • Nobel's test test for iliotibial band (ITB) syndrome, i.e. palpation of lateral tibial condyle causes ITB pain

  • Ober's test test for iliotibial band (ITB) syndrome, i.e. excessive tightness/tension on palpation of the ITB

  • patch test; skin test test of hypersensitivity, i.e. application of a range of potential sensitizing agents to skin (e.g. back, ulnar aspect of arm); degree of inflammatory reaction (provoked by test agents) is compared with a control (innocuous substance) and 'read'/assessed after 48-96 hours

  • pole test test to estimate foot systolic pressures in limbs with arterial calcification, i.e. with patient supine, leg is elevated until Doppler foot pulses cease, and elevation height (in cm) from apex of hallux to bench is noted and multiplied by 7.35

  • Romberg's test test comparing amount of body sway of an erect patient with eyes closed and eyes open; test is positive if patient shows loss of balance/increased tendency to sway when standing with eyes closed

  • screening test any test that categorizes by predetermined characteristic/property

  • single-leg raise test; tiptoe test test of tendo Achilles (TA), tibialis posterior and peroneal integrity/function, i.e. patient stands on one leg and weight-bears on tiptoe; patient with TA damage will not be able to rise normally to tiptoe on affected side; with TA rupture, patient will not be able to rise up on to tiptoe on the affected limb at all; heel pain during single-leg raise is indicative of Sever's disease see sever's

  • skin test see test, patch

  • talar tilt test test of integrity of lateral collateral ligament of the ankle, calcaneofibular ligament and tibialis posterior tendon, i.e. with the ankle joint at neutral (0° dorsiflexion) the calcaneum is passively inverted by the examiner; if the lateral collateral ligament is damaged (e.g. anterior talofibular ligament rupture) excessive talar excursion occurs; tissue dimpling inferior to the lateral malleolus indicates rupture of the calcaneofibular ligament; greater than expected talar eversion and flattening of the medial longitudinal arch indicate tibialis dysfunction

  • Thompson's test test of Achilles tendon function, i.e. with the patient lying prone, the posterior calf muscle group is squeezed, causing ankle joint plantarflexion; the foot does not plantarflex in total Achilles tendon rupture

  • thumb roll test test for 'runner's knee', i.e. the knee is flexed by 30-40° and the examiner's thumb rolled across the medial aspect of the patella, causing a painful 'snap' or 'click', and detection of a fibrous ridge/'shelf' at anterior knee compartment

  • Trendelenburg's test test of the quality of venous filling time, and quality of venous drainage in the leg, i.e. carried out as Buerger's test, but the time (in seconds) taken for the dorsal foot veins to refill and the direction of blood flow into the dorsal foot veins is noted; refill from proximal to distal indicates venous backflow and vein valve incompetence

  • Tuberculin test see Mantoux test

  • urea breath test test to detect Helicobacter pylori gastritis, or confirm its eradication, i.e. by analysis of exhaled breath

  • Valsalva's test test to detect autonomic neuropathy, i.e. the patient exhales into an empty plastic syringe (the other end of which is connected to a manometer to be maintained at 40mmHg) for 10 seconds, and changes in heart rate are noted (i.e. maximum expiratory heart rate and minimum heart rate after test cessation), and compared as a ratio; ratio of <1:10 indicates autonomic neuropathy (normal = >1:21)

  • vertical stress test test of plantar plate rupture, i.e. application of vertical stress to metatarsal head; translocation (i.e. > 2mm dorsal elevation) of base of toe in relation to dorsum of metatarsal head indicates plantar plate rupture

  • vibration test test of peripheral sensory function (assessing pacinian corpuscle function), i.e. application of vibration stimuli (from activated 128Hz tuning fork or neuraesthesiometer) to bony prominences (e.g. medial aspect of first metatarsophalangeal joint, lateral aspect of fifth metatarsal styloid process, medial and lateral malleoli, tibial tuberosity); vibrational awareness is reduced in the elderly and may be lost in diabetic distal sensory neuropathy, correlating with reduced pain awareness

References in periodicals archive ?
In November 2005, the American Gastroenterological Association (AGA) updated its position statement on the evaluation of dyspepsia to recommend testing in patients 55 years of age or younger without alarm symptoms with an active test such as the 13C-urea breath test or stool antigen test.
Before starting the study, all patients underwent a series of diagnostic tests, including a 13C-urea breath test (UBT) and endoscopy with biopsy, histology and culture to confirm infection with H.
in the Moscone Center, Hall D -- "A Novel Continuous 13C-Urea Breath Test for Detection of H.