[Lactose and bile acid absorption test--breath test using carbon radioisotope].
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Bile Acids and Salts↗
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Clinical evaluation of a 25 g D-xylose hydrogen (H2) breath test.
Breath hydrogen (H2) exhalation after xylose administration reflects the malabsorbed portion of the pentose and thus might facilitate the application of the D-xylose test. Therefore, as a complementary parameter, breath H2-exhalation in response to 25 g D-xylose was assessed in control subjects, in patients with coeliac disease, with chronic pancreatitis and with the irritable bowel syndrome. Patients with coeliac disease showed significantly higher breath H2 concentrations than the controls. Specificity and the positive predictive value of peak H2-increments greater than 56 ppm (i.e. greater than mean + 2 SD of controls) were 100%, but sensitivity was only 40%. In all patients with a positive H2 breath test, urinary D-xylose excretion and serum D-xylose increments were also abnormal. Apart from great overlap between controls and patients with coeliac disease, the failure to produce H2 in response to D-xylose in 12% of the 57 investigated subjects was the major factor limiting diagnostic efficiency of the test. Non H2 production could be shown to reflect a specific metabolic disability of the colonic flora and did not prove complete absorption of the substrate. It is concluded, that the 25 g D-xylose H2 breath test is of no clinical relevance for the diagnosis of celiac sprue but exaggerated breath H2 increases (greater than 56 ppm) with normal urinary and D-xylose tests were indicative for the irritable bowel syndrome in 5 out of 10 patients. The diagnostic impact of this constellation thus merits further investigation.
Adult↗
New immunoassay for the detection of Helicobacter pylori infection compared with urease test, 13C breath test and histology: validation in the primary care setting.
Helicobacter pylori plays a major role in peptic ulcer disease and, as a result, testing for H. pylori infection among patients with dyspepsia has often been advocated. The aim of the study was to determine the diagnostic accuracy, the analytical performance, and optimal cut-off point of a new serological assay, the Pyloriset EIA-G III for the detection of H. pylori infection in the primary care setting. For 113 primary care patients with dyspepsia urea breath test, CLO test, histology and serology tests were performed. Diagnostic accuracy of the Pyloriset EIA-G III was evaluated against a reference standard of a carbon urea breath test (CUBT), CLO test and histology (from gastric biopsies). Precision, linearity and correlation of the serological assay with the CUBT and former Pyloriset were also determined. At the optimal cut-off level of 40 U/ml, the positive predictive value was 92.1%, negative predictive value 96.3%, sensitivity 87.5%, and specificity 93.9%. The within-run precision was high. The recovery data were good. The correlation of both CUBT and the former Pyloriset EIA-G and the Pyloriset EIA-G III was high. At the cut-off level of 40 U/ml, the new Pyloriset EIA-G III is a reliable method to detect H. pylori infection in the primary care setting.
Adult↗
Helicobacter pylori and urea breath testing. Can the breath test result predict the outcome of treatment?
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Anti-Ulcer Agents↗
[Respiratory tests or breath tests (BT). Recent pediatric applications].
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Breath Tests↗
Alcohol breath tests and breath deodorization by chlorophyll derivatives.
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Alcoholic Intoxication↗
Comparison of the 1-gram (14)C-D-xylose breath test and the 50-gram hydrogen glucose breath test for diagnosis of small intestinal bacterial overgrowth.
BACKGROUND/AIMS: Culture of small bowel aspirate is the most direct method and the gold standard for diagnosing small intestinal bacterial overgrowth. However, cultures are cumbersome and fluoroscopy is required for obtaining aspirate. Therefore, different breath tests such as the xylose breath test and the hydrogen breath test have been developed. There is no general agreement as to which test is to be preferred. In the only previous direct comparison between these two tests an advantage for the 1-gram-(14)C-D-xylose breath test was found. The aim of the study was to compare the 50-gram glucose hydrogen breath test and the 1-gram (14)C-D-xylose breath test in relation to results of cultures of small bowel aspirate. METHODS: Forty-six consecutive patients, mean age 57 (range 27-87) years, 12 men and 34 women, were included because of suspicion of small intestinal bacterial overgrowth. After small bowel aspiration, all patients received a solution of 1 g xylose, labelled with 50 microg (14)C-D-xylose, and 50 g glucose dissolved in 250 ml water. The concentration of breath hydrogen was analyzed every 15 min for 2 h and (14)CO(2) was analyzed every 30 min for 4 h. A positive hydrogen breath test was defined as a rise in hydrogen concentration of 15 ppm. A positive xylose test was defined as an accumulated dose 4.5% after 4 h. Two definitions for a positive culture were used, either growth of 10(5 )colonic-type bacteria/ml or growth of 10(5) bacteria/ml of any type. RESULTS: Twenty-four patients had growth of 10(5) bacteria, of whom 10 had growth of 10(5) colonic-type bacteria in small bowel aspirate. Twenty-two patients had no significant growth. The hydrogen breath test and the xylose breath test had a sensitivity for growth of 10(5) bacteria of 58 and 42%, respectively. For growth of 10(5 )colonic-type bacteria the sensitivity was 90% for the hydrogen breath test and 70% for the xylose breath test. The specificity was similar for the two tests. CONCLUSION: Although no significant difference between the two tests was found, there was a tendency in favor of the 50-gram glucose hydrogen breath test. The simplicity in combination with high sensitivity makes the hydrogen breath test suitable as a screening method to select patients for further investigation.
Adult↗
13C-galactose breath test and 13C-aminopyrine breath test for the study of liver function in chronic liver disease.
BACKGROUND AND AIMS: Liver biopsy examination is the gold standard to diagnose the presence of cirrhosis. The aim of this study was to evaluate the accuracy of both 13 C-aminopyrine breath test ( 13 C-ABT) and 13 C-galactose breath test ( 13 C-GBT) in the noninvasive assessment of the presence of cirrhosis in patients with chronic liver disease. METHODS: We evaluated 61 patients with chronic liver disease of diverse etiologies (21 compensated cirrhosis). All patients underwent 13 C-GBT and 13 C-ABT, and the results were expressed as a percentage of the administered dose of 13 C recovered per hour (%dose/h) and as the cumulative percentage of administered dose of 13 C recovered over time (%dose cumulative). Results were analyzed according to absence vs presence of cirrhosis. RESULTS: On average, 13 C-GBT %dose/h and %dose cumulative were decreased significantly in patients with compensated cirrhosis, and the same finding was observed for 13 C-ABT results from 30 to 120 minutes. 13 C-GBT %dose/h at 120 minutes had 71.4% sensitivity, 85.0% specificity, and 83.7% accuracy, whereas 13 C-ABT %dose cumulative at 30 minutes had 85.7% sensitivity, 67.5% specificity, and 77.1% accuracy for distinguishing between the 2 subgroups of patients. Combined assessment of 13 C-GBT and 13 C-ABT increased the diagnostic accuracy (80% positive predictive value) of either test alone and reached 92.5% specificity and 100% sensitivity for the diagnosis of cirrhosis. CONCLUSIONS: In patients with chronic liver disease, both 13 C-GBT and 13 C-ABT are useful for the diagnosis of cirrhosis. Combination of the tests increases the diagnostic yield of each test alone.
Adult↗
Comparison of the one-gram d-[14C]xylose breath test to the [14C]bile acid breath test in patients with small-intestine bacterial overgrowth.
In twelve patients with culture-proven bacterial overgrowth of the small intestine, the ability of a newly-developed one-gram d-[14C]xylose breath test to detect bacterial overgrowth was compared to that of the [14C]bile acid breath test. All patients manifested excessive production of breath 14CO2 after the administration of one gram [14C]xylose, with 83% of the patients being abnormal within the first hour of testing. In contrast, during the [14C]bile acid breath test, four of the twelve patients had no period of excessive 14CO2 production (above the 95% confidence range of controls). Nutrient malabsorption (fat, cobalamin, xylose) was seen with both true-positive and false-negative bile acid breath tests. The one gram [14C]xylose breath test, utilizing a substrate with more predominant absorption in the proximal small intestine and which can be catabolized by Gram-negative aerobic bacteria, appears to have a greater degree of sensitivity and specificity than the bile acid breath test in detecting the presence of small-intestine bacterial overgrowth.
Bacterial Infections↗
Accuracy of a new monoclonal stool antigen test in post-eradication assessment of Helicobacter pylori infection: comparison with the polyclonal stool antigen test and urea breath test.
BACKGROUND AND AIM: The enzyme immunoassay based on polyclonal antibodies (HpSA) represents a valid method for the detection of Helicobacter pylori antigens in stool specimens, but some controversial results were reported in post-eradication setting. A new monoclonal enzyme immunoassay (FemtoLab H. pylori, Connex) has been developed. The present study compares the diagnostic accuracy of the two tests after eradication therapy. PATIENTS AND METHODS: Stool samples were collected and urea breath test and endoscopy performed in 325 patients (161 F, 164 M, age 17-78 years), 4-8 weeks after standard triple eradication therapy. The FemtoLab and HpSA tests were performed in accordance with the manufacturer's protocol. H. pylori infection was confirmed if culture alone or both urease test and histology were positive and was considered absent if all three tests were negative. RESULTS: H. pylori was eradicated in 231 patients (71.1%). Urea breath test showed the best performances with sensitivity 98.9% and specificity 99.5%. The sensitivity of FemtoLab was 88.3%, specificity 94.8%, positive and negative predictive values 87.4% and 95.2%. Corresponding HpSA values were 73.4%, 97.8%, 93.2% and 90%. Sensitivity and negative predictive value of FemtoLab were significantly better than HpSA. Adjusting the cut-offs according to a ROC curve improved not significantly the sensitivity of the two tests. CONCLUSIONS: Urea breath test shows the best accuracy in the assessment of H. pylori infection. Between the stool tests, the FemtoLab due to its higher sensitivity is to prefer in the post-eradication assessment of H. pylori infection.
Adolescent↗
Comparative clinical evaluation of the 13C-mixed triglyceride breath test as an indirect pancreatic function test.
BACKGROUND: Breath tests using stable isotopes of carbon or hydrogen are increasingly becoming established for the evaluation of various gastrointestinal functions, including measurement of exocrine pancreatic insufficiency. We wanted to evaluate the clinical relevance of the non-invasive, non-radioactive 13C-mixed triglyceride breath test in comparison with the secretin-caerulein test as the 'gold standard' of pancreatic function testing and with faecal chymotrypsin and elastase 1 in patients with mild and severe exocrine pancreatic insufficiency. METHODS: The secretin-caerulein test, faecal fat analysis, 13C-mixed triglyceride breath test, faecal elastase 1, and chymotrypsin and various morphologic investigations were done in 26 patients with mild (n = 13) or severe (n = 13) exocrine pancreatic insufficiency and 25 patients with gastrointestinal diseases of non-pancreatic origin. Twenty-seven healthy volunteers served as normal controls. After a 12-h fast 200 mg mixed triglyceride (1,3-distearyl,2(carboxyl-13C)octanoyl glycerol) were orally administered with a test meal, and breath samples were taken before and at 30-min intervals for 5 h thereafter, and the increase in 13C/12C isotopic ratio in breath was analysed by mass spectrometry. Various modifications of the test procedure were investigated. RESULTS: Specificity for impaired pancreatic function was higher for faecal elastase (90%) and equal for faecal chymotrypsin (82%) as compared with the various variables of the 13C-mixed triglyceride breath test (69-85%). The sensitivity of the 13C-mixed triglyceride breath test for total and separately for mild and severe exocrine pancreatic insufficiency was higher (total, 69-81%) than that of faecal chymotrypsin (total, 56%) but lower than faecal elastase (total, 92%). CONCLUSION: The 13C-mixed triglyceride breath test very sensitively reflects severe exocrine pancreatic insufficiency (steatorrhoea) but has limited sensitivity for the detection of mild cases. With regard to the higher sensitivity and specificity, the higher practicability, and the much lower cost, determination of faecal elastase 1 concentrations is superior to the 13C-mixed triglyceride breath test and therefore remains the most reliable indirect pancreatic function test available today.
Adult↗
Diagnosis of Helicobacter pylori infection: validation of a commercial non invasive salivary test against urea breath test and serology.
BACKGROUND: Helicobacter pylori (H. pylori) infection plays an important role in the pathogenesis of chronic gastritis, peptic ulcer disease, MALT lymphoma and gastric cancer. Recently Helicobacter spp. infection has been correlated with cirrhosis, hepatocellular carcinoma and acute myocardial infarction. Several invasive and non-invasive tests have been proposed for the detection of the bacterium. In clinical practice, the selection of the appropriate test will depend on the disease and on cost-effectiveness. Aim of the study was to validate a rapid, salivary test for detecting the presence of antibodies against H. pylori in a population of patients undergoing to the 13C-urea breath test (13C-UBT). METHODS: Saliva and serum samples were obtained from 91 patients (47 females, mean age 53+/-6.7 years) attending the 13C-UBT service between 15 September and 31 November 1999. Thirty-five of them had had a previous diagnosis of peptic ulcer at endoscopy and 46 out of 91 had a diagnosis of histologically confirmed chronic gastritis. 39 out of 91 were dyspeptic patients with no symptoms suspect for peptic ulcer or cancer. Patients were excluded from the 13C-UBT if they had been treated with inhibitors of acid secretion and antibiotics within 30 days before testing. Breath sample were collected at baseline and 30 minutes after the ingestion of orange juice and a 75 mg dose of 13C-labeled urea. The presence in serum of antibodies (IgG) against the bacterium was assessed by means of a commercial enzyme immunosorbent assay with a reported sensitivity of 94% and specificity of 87%. Saliva was collected using a sterile absorbent pad placed between the mandibular gum and the cheek in the mouth and assayed for H. pylori antibodies by an immunochromatographic rapid method. RESULTS: Thirty-seven of the 91 patients were defined positive by 13C-UBT and serological test. Twenty-nine of these 37 were identified as positive by the salivary test. Fifty-four patients were defined as negative but the salivary test identified 13 of them as positive, thereby sensitivity and specificity were 78.3 and 75.9% respectively. The accuracy was 76.9%. Positive predictive value was 69% and negative predictive value 83.6%. CONCLUSIONS: The salivary test could be considered in the ambulatory setting, as a non-invasive tool for the screening of H. pylori infection, when more accurate methods are not available.
Journal Article↗
Aminopyrine breath test: development of a 13C-breath test for quantitative assessment of liver function in humans.
BACKGROUND/AIM: 14C-aminopyrine breath test (ABT) has been shown to be well correlated to the severity of liver diseases, but its use is limited in countries where radioactive isotopes are severely controlled. The goal of this study was to develop a 13C-ABT based on a highly sensitive method to measure 13CO2 in breath samples. MATERIALS AND METHODS: The relevant parameters were studied in 26 controls and 27 patients: the 13CO2 enrichment of expired breath between t-10 and t+60 minutes was determined as the most simple and clinically useful parameter. The 13C-ABT was then prospectively compared to clinico-biological data and the galactose elimination capacity (GEC) in 82 patients. RESULTS: The 13C-ABT was well correlated to: i) the Child-Pugh classification; ii) GEC results; iii) the hepatic volume. The presence of ascites or alcoholic consumption did not alter significantly the results of the test. 13C-ABT appeared more sensitive than GEC to evaluate minor liver dysfunctions. CONCLUSIONS: The 13C-ABT is a simple and sensitive test to measure liver function. The use of the stable isotope 13C ensures the harmlessness of the test and the possibility to repeat it in a given patient.
Adult↗
A combination of the Helicobacter pylori stool antigen test and urea breath test is useful for clinical evaluation of eradication therapy: a multicenter study.
BACKGROUND: Helicobacter pylori stool antigen (HpSA) test is a new tool for evaluating the H. pylori infection. The present study was carried out to investigate the clinical usefulness of the HpSA test in the evaluation of eradication therapy by comparing it with the (13)C-urea breath test (UBT). METHODS: One hundred and five patients received eradication therapy for H. pylori. After more than 8 weeks, the success of the therapy was evaluated by the HpSA test and the UBT. Concordant results were regarded as a final diagnosis, but when the results were discordant, histological examination was carried out. RESULTS: Of the 105 patients receiving eradication therapy for H. pylori, 25 patients were regarded as H. pylori positive by the UBT and and 20 patients were regarded as H. pylori positive by the the HpSA test. Nine patients (8.6%) showed discordant results (seven cases with UBT(+) and HpSA(-), and two with UBT(-) and HpSA(+)). Five cases out of nine were ultimately judged as having a false-positive result of the UBT, and in these cases the UBT values were relatively low (below 10 per thousand). The final diagnostic accuracies of the UBT and the HpSA test were 94.3% (88.0-97.9%; 95% CI) and 97.1% (91.9-99.4%), respectively. When we used the HpSA test in cases with weakly positive UBT values, we were able to diagnose the correct status of H. pylori infection after eradication in 99% of all patients (94.8-100.0%). CONCLUSION: The HpSA test is a useful tool for the evaluation of eradication therapy and a combination of the HpSA test and UBT is clinically recommended.
Adult↗
Estimation of 14C-triolein assimilation as a test of lipid assimilation. Breath test or measurement of serum radioactivity?
Two tests of lipid assimilation based on estimation of 14C-triolein assimilation from expiratory 14CO2 (breath test) and from serum radioactivity of 14C, respectively, were investigated in 48 consecutive patients suspected of having malassimilation. Patients with proven malassimilation had significantly lower expiration of 14CO2 and lower serum radioactivity of 14C than patients with normal lipid assimilation. The se-14C test correctly diagnosed significantly more patients with malassimilation than the breath test; the diagnostic efficiencies were 0.87 and 0.74, respectively. The results of both tests correlated with measurement of faecal fat. However, within the group of patients with proven malassimilation the results of the breath test correlated poorly with faecal fat, whereas a significant correlation was found between the se-14C test and faecal fat within this group. Correspondingly, the correlation between the results of the breath test and the se-14C test was poor, indicating that intermediate metabolism influences the results.
Adult↗
13C abundances of nutrients and the effect of variations in 13C isotopic abundances of test meals formulated for 13CO2 breath tests.
Unlike 14CO2 breath tests, 13CO2 breath tests are performed in the presence of a large background of naturally occurring isotope. Because the exact abundance of 13CO2 in breath can be changed by variations in diet, a study of the 13C abundance of dietary constituents and their effects on breath 13CO2 has been undertaken. Dietary constituents have been combusted to CO2 and the relative abundance of 13C analyzed by mass spectrometry. Breath CO2 was collected and isotopically analyzed after the ingestion of several dietary constituents and test meals. The 13CO2 abundance of breath CO2 was shown to change in response to the 13C abundance of the substrate being oxidized. Conversely, a test meal that closely approximates the 13C abundance of fasting breath CO2 from North Americans was shown not to alter the 13CO2 abundance in breath. Investigation of the breath 13CO2 response to individual 13C-labeled dietary constituents demonstrated that amino acids produced the earliest 13CO2 response followed in order by medium chain triglycerides, carbohydrates, and long chain triglycerides. Because of the variation in 13C abundances in nature, the 13C abundance of any unlabeled substrate ingested during a 13CO2 breath test must be considered in order to eliminate artifacts that may reduce the sensitivity of the breath test or produce erroneous results. Methods for correcting breath tests for changes in background 13CO2 abundance are also discussed.
Adult↗
A comparison of the structure and function of the terminal ileum in Crohn's disease using radiology, the "Dicopac" Schilling test and [14C] G.C.A. breath test.
Twenty patients with Crohn's disease were studied. Thirteen had radiological evidence of involvement of the terminal ileum. None had significant bacterial overgrowth of the small bowel contents and none had had resection of the terminal ileum. In all patients a [14C] glycocholic acid ([14C] G.C.A.) breath test and a "Dicopac" Schilling test were performed to assess terminal ileal function. The data showed poor correlation between the radiological appearance of the terminal ileum and the results of the functional tests. There was also poor correlation between the results of the [14C] G.C.A. breath test and the "Dicopac" Schilling test. Without terminal ileal histology, any assessment of the extent of Crohn's disease of the terminal ileum and of its effect on terminal ileal function, must include the [14C] G.C.A. breath test as well as radiology and the "Dicopac" Schilling test. The limitations of the [14C] G.C.A. breath test as a test of terminal ileal function in Crohn's disease are discussed.
Breath Tests↗
Measurement of fat digestion in early life using a stable isotope breath test.
13C breath tests are a safe, non-invasive way of assessing nutrient digestion and absorption that can be used repeatedly in infancy and childhood. The aim of this study was to assess their value for measuring fat digestion in infants and young children with cystic fibrosis, and healthy controls whose pancreatic exocrine function is immature, and to monitor pancreatic enzyme supplementation. Six infants with cystic fibrosis (aged 10-18 months) and nine healthy controls (aged 6-19 months) were studied. After an overnight fast each child ingested 7.5 mg/kg 13C trioctanoin (99 atom % excess) followed by a known volume of milk. Breath samples were collected before and at 30 minute intervals thereafter for five hours. The 13C enrichment of expired carbon dioxide was measured by gas isotope ratio mass spectrometry. The mean (SD) percentage dose recovery of 13C was 13.5 (5.3) for the cystic fibrosis group and 24.2 (6.7) for the healthy controls. When those with cystic fibrosis were studied after supplementary pancreatic enzymes, the mean percentage dose recovery rose to 17.1 (6.9). Total intraluminal lipolysis was diminished by 44% in young children with cystic fibrosis. Pancreatic enzyme supplements improved digestion by 27%. The 13C trioctanoin breath test was effective in detecting fat maldigestion and can be used to measure the benefits of enzyme supplements in early life.
Breath Tests↗