Urea breath test

Non-endoscopic testing methods include the urea breath test, serologic testing, and the stool antigen assay. Compared to endoscopic procedures, these tests are more comfortable, less expensive, and do not require a special procedure. The urea breath test is usually the first-line test to detect active... 

Office-based serologic testing provides a quick assessment (within 15 minutes) of an exposure to HP, but patients can remain seropositive for up to 1 year after eradication, making the clinical utility of this test limited. Stool antigen assays can be useful for the initial diagnosis or to confirm HP eradication, and unlike the urea breath test, are less affected by concomitant medication use.9... 

Table 2 gives details of some conventional regimes (see British National Formulary, 2008). The efficacy of therapy can be checked by Radiocarbon-labelled urea breath testing (which depends upon release of labelled carbon dioxide by bacterial urease) or by testing gastric biopsy material for persistence of gastric urease, but should only be done after eradication therapy has been discontinued for at least a month, and whilst any anti-secretory treatment has been discontinued (because it tends to suppress but does not eradicate the organism). 

It is not usually necessary to check for successful eradication unless the patient continues to have symptoms. Under these circumstances the urea breath test is a useful noninvasive technique. 

The urea breath test measures radiolabelled COj in expired air after ingestion of labelled urea, exploiting the fact that the organism produces urease and can convert urea to ammonia. 

H. pylori produces urease, and hydrolysis of endogenous urea to bicarbonate and ammonia may create a more hospitable microenvironment for the survival of the organism in the stomach. Mammalian cells do not hydrolyze urea and it was only in 1984 that gastric urease was associated with the presence of H. pylori The ability of the organism to rapidly hydrolyze urea is the basis of the urea breath tests and of the direct urease tests on gastric biopsy samples. 

In the stool test, specific H. pylori antigens are detected in microtiter plates coated with polyclonal antibodies. Debate continues regarding its accuracy for assessing treatment outcome some of the variability in results between different studies appears to be caused by lack of standardization of the interval between completion of eradication therapy and stool testing.However, the test is currently recommended for posteradication testing if the urea breath test is not available. 

Koletzko S, Haisch M, Seeboth I, Braden B, Hengels K, Koletzko B, Hering P. Isotope-selective non-disper-sive infrared spectrometry for detection of Helicobacter pylori infection with C-urea breath test. Lancet 1995 345 961-2. 

Logan RPH, Dill S, Bauer FE, Walker MM, Hirschl AM, Gummett PA, et al. The European C-urea breath test for the detection of Helicobacter pylori Eur J Gastroenterol Hepatol 1991 3 915-21. 

Infection by H. pylori is detected by serological markers produced by host immune responses (e.g., antibodies to antigens of H. pylori) and a breath test. The latter, known as the urea breath test, consists of oral administrations of radioactively labeled urea. This is metabolized to labeled CO2 and ammonia by the urease of H. pylori present in the gastric mucosa. The presence of labeled CO2 measured in the exhaled air confirms infection. 

The nonendoscopic tests (see Table 33-6) include serologic antibody detection tests, the urea breath test (UBT), and the stool antigen... 

Urea breath test HP urease breaks down ingested labeled C-urea, patient exhales labeled CO2 Tests for active HP infection 95% sensitive and specific results take about 2 days antibiotics, bismuth, PPIs, and H2RAS may cause false-negative results withhold PPIs or H2RAS (1 to 2 weeks) and bismuth or antibiotics (2 to 4 weeks) before testing may be used posttreatment to confirm eradication... 

Stool antigen Identifies HP antigen in stool, leading to color change that can be detected visually or by spectrophotometer Tests for active HP infection sensitivity and specificity comparable to urea breath test when used for initial diagnosis antibiotics, bismuth, and PPIs may cause false-negative results, but to a lesser extent than with the urea breath test may be used posttreatment to confirm eradication... 

Bilardi C, Biagini R, Dulbecco P, et al. Stool antigen assay (HpSA) is less reliable than urea breath test for post-treatment diagnosis of Helicobacter pylori infection. Aliment Pharmacol Ther 2002 16 1733-1738. 

Ability of H. pylori to produce urease is clinically used for detection by the [13C]-urea breath test and clofazimine (CLO) tests. Other methods of detection include biopsy (histologic identification is the gold standard) and serology. 

Urea breath test Used to identify patients with HeScobaclerpylori rltec6on which is strongly associated with peptic ulcer disease... 

It was possible to predict the presence of the bacteria without the need for performing the standard C-urea breath tests. Breath samples from 11 patients and 22 healthy volunteers were collected and immediately analyzed by the electronic nose consisting of eight thickness shear-mode sensors. Data analysis was by linear discriminate analysis (LDA), and it was found that 87.5% of the patients were correctly classified. 

In the presence of peptic ulcer disease, it is important to identify the presence of H. pylori before the institution of therapy so that eradication of the organism can be confirmed 4 to 6 weeks after treatment. In this respect, successful eradication can be documented in duodenal ulcer patients by use of the noninvasive urea breath test. In individuals with gastric ulceration, endoscopy is necessary not only to confirm adequate healing but also to ensure that no neoplasia exists. 

The effect of acidification on the rate of gastric emptying on the right and the urea breath test (UBT) on the left. It can be seen that there is an improvement in the UBT either with apple juice (pH 3.0) or acidification of a test meal (Ensure) but that apple juice is emptied more quickly and that there is no difference in the emptying of either neutral or acidified Ensure. 

Endoscopy cannot be justified merely to diagnose H. pylori infection. As a noninvasive test, the urea breath test is extremely useful, particularly in establishing whether active infection exists or if eradication therapy has been successful. 

Chey WD, Fey D, Scheirman JM, et al. Role of acid suppression in the effects of lansoprazole and ranitidine on the 14C urea breath test. In Graham DY, Blazer MJ, eds. Developments in Helicobacter research. 1997 17-18 (abstract). 

Domiguez-Munoz JE, Leodolter A, Sauerbruch T, et al. A citric acid solution is an optimal test drink in the 13C urea breath test for diagnosis of Helicobacter pylori infection. Gut 1997 40 459-462. 

Lotterer, E., Ludtke, F.E., Tegeler, R., Lepsien, G. and Bauer, F.E., The C-urea breath test— detection of Helicobacter pylori infection in patients with partial gastrectomy. Z Gastroenterol, 31, 115-119 (1993). 

Cutler, A.F. and Toskes, P., Comparison of Xl-urea blood test to Xl-urea breath test for the diagnosis of Helicobacter pylori. Am. J. Gastroenterol, 94, 959-961 (1999). 

Mion F, Delecluse HJ, Rousseau M, Berger F, Brazier JL, Minaire Y (1994) C-urea breath test for the diagnosis of Helicobacter pylori infection. Comparison with histology. Gastroenterol Clin Biol 18 1106-1111... 

Goddard AF, Logan RPH (1997) Review article urea breath tests for detecting Helicobacter pylori. Aliment Pharmacol Ther 11 641 -649... 

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