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EBioMedicine Aug 2019Breath tests may diagnose tuberculosis (TB) through detecting specific volatile organic compounds produced by Mycobacterium tuberculosis or the infected host. (Meta-Analysis)
Meta-Analysis
BACKGROUND
Breath tests may diagnose tuberculosis (TB) through detecting specific volatile organic compounds produced by Mycobacterium tuberculosis or the infected host.
METHODS
To estimate the diagnostic accuracy of breath test with electronic-nose and other devices against culture or other tests for TB, we screened multiple databases until January 6, 2019.
FINDINGS
We included fourteen studies, with 1715 subjects in the analysis. The pooled sensitivity and specificity of electronic-nose were 0.93 (95% CI 0.82-0.97) and 0.93 (95% CI 0.82-0.97), respectively, and no heterogeneity was found. The sensitivity and specificity of other breath test devices ranged from 0.62 to 1.00, and 0.11 to 0.84, respectively.
INTERPRETATION
The low to moderate evidence of these studies shows that breath tests can diagnose TB accurately, however, to give a real-time test result, additional development is needed. Research should also focus on sputum smear negative TB, children, and the positioning of breath testing in the diagnostic work flow.
FUNDING
The authors received no specific funding for this work.
Topics: Biosensing Techniques; Breath Tests; Electronic Nose; Female; Humans; Male; Mycobacterium tuberculosis; ROC Curve; Reproducibility of Results; Sensitivity and Specificity; Tuberculosis; Tuberculosis, Pulmonary; Volatile Organic Compounds
PubMed: 31401197
DOI: 10.1016/j.ebiom.2019.07.056 -
Journal of Applied Physiology... Aug 2016The alcohol breath test is reviewed with a focus on gas exchange factors affecting its accuracy. The basis of the alcohol breath test is the assumption that alveolar air... (Review)
Review
The alcohol breath test is reviewed with a focus on gas exchange factors affecting its accuracy. The basis of the alcohol breath test is the assumption that alveolar air reaches the mouth during exhalation with no change in alcohol concentration. Recent investigations have shown that alcohol concentration is altered during its transit to the mouth. The exhaled alcohol concentration is modified by interaction with the mucosa of the pulmonary airways. Exhaled alcohol concentration is not an accurate indicator of alveolar alcohol concentration. Measuring alcohol concentration in the breath is very different process than measuring a blood level from air equilibrated with a blood sample. Airway exchange of alcohol leads to a bias against certain individuals depending on the anatomic and physiologic characteristics. Methodological modifications are proposed to improve the accuracy of the alcohol breath test to become fair to all.
Topics: Breath Tests; Computer Simulation; Ethanol; Exhalation; Female; Humans; Lung; Male; Models, Biological; Pulmonary Gas Exchange; Reproducibility of Results; Sensitivity and Specificity
PubMed: 27197859
DOI: 10.1152/japplphysiol.00548.2015 -
Breath Test: Clinical Application of Breath Analysis in Lower Respiratory Tract Infection Diagnosis.The Pediatric Infectious Disease Journal Nov 2021
Review
Topics: Bacteria; Breath Tests; Child; Humans; Mass Spectrometry; Respiratory Tract Infections; Viruses; Volatile Organic Compounds
PubMed: 34591801
DOI: 10.1097/INF.0000000000003310 -
Current Gastroenterology Reports Feb 2016Small intestinal bacterial overgrowth (SIBO) is characterized by an excessive amount of bacteria in the small intestine and a constellation of symptoms that include... (Review)
Review
Small intestinal bacterial overgrowth (SIBO) is characterized by an excessive amount of bacteria in the small intestine and a constellation of symptoms that include bloating, pain, gas, and diarrhea. Although known for many decades, there is a lack of consensus and clarity regarding the natural history and methods for its diagnosis. Several tests have been proposed, including the glucose breath test, lactulose breath test, small intestinal aspiration and culture, and others. However, there is a lack of standardization of these tests and their interpretation. Treatment of SIBO remains empirical; generally, broad spectrum antibiotics are recommended for 2 weeks (amoxicillin, rifaximin, ciprofloxacin, etc.) but evidence for their use is fair. Clearly, there is a strong need to develop a systematic approach for the management of SIBO and to perform multicenter clinical trials for the treatment of SIBO. In this review, we will discuss the current evidence for the diagnosis and treatment of SIBO, which includes (1) elimination/modification of the underlying causes, (2) induction of remission (antibiotics and elemental diet), and (3) maintenance of remission (promotility drugs, dietary modifications, repeat or cyclical antibiotics).
Topics: Anti-Bacterial Agents; Bacteriological Techniques; Blind Loop Syndrome; Breath Tests; Evidence-Based Medicine; Humans; Intestine, Small
PubMed: 26780631
DOI: 10.1007/s11894-015-0482-9 -
BMJ Open Diabetes Research & Care May 2021The review aimed to investigate the accuracy of breath tests in the diagnosis of diabetes mellitus, identify exhaled volatile organic compounds with the most evidence as... (Meta-Analysis)
Meta-Analysis Review
The review aimed to investigate the accuracy of breath tests in the diagnosis of diabetes mellitus, identify exhaled volatile organic compounds with the most evidence as potential biomarkers, and summarize prospects and challenges in diabetic breath tests. Databases including Medline, PubMed, EMBASE, Cochrane Library and Science Citation Index Expanded were searched. Human studies describing diabetic breath analysis with more than 10 subjects as controls and patients were included. Population demographics, breath test conditions, biomarkers, analytical techniques and diagnostic accuracy were extracted. Quality assessment was performed with the Standards for Reporting Diagnostic Accuracy and a modified QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2). Forty-four research with 2699 patients with diabetes were included for qualitative data analysis and 14 eligible studies were used for meta-analysis. Pooled analysis of type 2 diabetes breath test exhibited sensitivity of 91.8% (95% CI 83.6% to 96.1%), specificity of 92.1% (95% CI 88.4% to 94.7%) and area under the curve (AUC) of 0.96 (95% CI 0.94 to 0.97). Isotopic carbon dioxide (CO) showed the best diagnostic accuracy with pooled sensitivity of 0.949 (95% CI 0.870 to 0.981), specificity of 0.946 (95% CI 0.891 to 0.975) and AUC of 0.98 (95% CI 0.97 to 0.99). As the most widely reported biomarker, acetone showed moderate diagnostic accuracy with pooled sensitivity of 0.638 (95% CI 0.511 to 0.748), specificity of 0.801 (95% CI 0.691 to 0.878) and AUC of 0.79 (95% CI 0.75 to 0.82). Our results indicate that breath test is a promising approach with acceptable diagnostic accuracy for diabetes mellitus and isotopic CO is the optimal breath biomarker. Even so, further validation and standardization in subject control, breath sampling and analysis are still required.
Topics: Biomarkers; Breath Tests; Diabetes Mellitus, Type 2; Humans; Reference Standards
PubMed: 34031142
DOI: 10.1136/bmjdrc-2021-002174 -
Clinical and Translational... Apr 2023There is increasing appreciation that small intestinal bacterial overgrowth (SIBO) drives many common gastrointestinal symptoms, including diarrhea, bloating, and... (Review)
Review
There is increasing appreciation that small intestinal bacterial overgrowth (SIBO) drives many common gastrointestinal symptoms, including diarrhea, bloating, and abdominal pain. Breath testing via measurement of exhaled hydrogen and methane gases following ingestion of a readily metabolized carbohydrate has become an important noninvasive testing paradigm to help diagnose SIBO. However, because of a number of physiological and technical considerations, how and when to use breath testing in the diagnosis of SIBO remains a nuanced clinical decision. This narrative review provides a comprehensive overview of breath testing paradigms including the indications for testing, how to administer the test, and how patient factors influence breath testing results. We also explore the performance characteristics of breath testing (sensitivity, specificity, positive and negative predictive values, likelihood ratios, and diagnostic odds ratio). Additionally, we describe complementary and alternative tests for diagnosing SIBO. We discuss applications of breath testing for research. Current estimates of SIBO prevalence among commonly encountered high-risk populations are reviewed to provide pretest probability estimates under a variety of clinical situations. Finally, we discuss how to integrate breath test performance characteristics into clinical care decisions using clinical predictors and the Fagan nomogram.
Topics: Humans; Intestine, Small; Methane; Diarrhea; Hydrogen; Breath Tests
PubMed: 36744854
DOI: 10.14309/ctg.0000000000000567 -
Lipids Jul 2022Gastric emptying (GE) is the process of food being processed by the stomach and delivered to the small intestine where nutrients such as lipids are absorbed into the... (Review)
Review
Gastric emptying (GE) is the process of food being processed by the stomach and delivered to the small intestine where nutrients such as lipids are absorbed into the blood circulation. The combination of an easy and inexpensive method to measure GE such as the CO breath test using the stable isotope [ C]octanoic acid with semi-mechanistic modeling could foster a wider application in nutritional studies to further understand the metabolic response to food. Here, we discuss the use of the [ C]octanoic acid breath test to label the solid phase of a meal, and the factors that influence GE to support mechanistic studies. Furthermore, we give an overview of existing mathematical models for the interpretation of the breath test data and how much nutritional studies could benefit from a physiological based pharmacokinetic model approach.
Topics: Breath Tests; Caprylates; Carbon Isotopes; Gastric Emptying
PubMed: 35799422
DOI: 10.1002/lipd.12352 -
Clinical Gastroenterology and... Dec 2014The diagnosis of small intestinal bacterial overgrowth (SIBO) has increased considerably owing to a growing recognition of its association with common bowel symptoms... (Review)
Review
The diagnosis of small intestinal bacterial overgrowth (SIBO) has increased considerably owing to a growing recognition of its association with common bowel symptoms including chronic diarrhea, bloating, abdominal distention, and the irritable bowel syndrome. Ideally, an accurate and objective diagnosis of SIBO should be established before initiating antibiotic treatment. Unfortunately, no perfect test exists for the diagnosis of SIBO. The current gold standard, small-bowel aspiration and quantitative culture, is limited by its high cost, invasive nature, lack of standardization, sampling error, and need for dedicated infrastructure. Although not without shortcomings, hydrogen breath testing provides the simplest noninvasive and widely available diagnostic modality for suspected SIBO. Carbohydrates such as lactulose and glucose are the most widely used substrates in hydrogen breath testing, with glucose arguably providing greater testing accuracy. Lactose, fructose, and sorbitol should not be used as substrates in the assessment of suspected SIBO. The measurement of methane in addition to hydrogen can increase the sensitivity of breath testing for SIBO. Diagnostic accuracy of hydrogen breath testing in SIBO can be maximized by careful patient selection for testing, proper test preparation, and standardization of test performance as well as test interpretation.
Topics: Blind Loop Syndrome; Breath Tests; Glucose; Humans; Hydrogen; Intestine, Small; Lactulose; Methane
PubMed: 24095975
DOI: 10.1016/j.cgh.2013.09.055 -
Biosensors Jun 2023The urea breath test is a non-invasive diagnostic method for infections, which relies on the change in the proportion of CO in exhaled air. Nondispersive infrared...
The urea breath test is a non-invasive diagnostic method for infections, which relies on the change in the proportion of CO in exhaled air. Nondispersive infrared sensors are commonly used for the urea breath test in laboratory equipment, but Raman spectroscopy demonstrated potential for more accurate measurements. The accuracy of the detection via the urea breath test using CO as a biomarker is affected by measurement errors, including equipment error and δC measurement uncertainty. We present a Raman scattering-based gas analyzer capable of δC measurements in exhaled air. The technical details of the various measurement conditions have been discussed. Standard gas samples were measured. CO and CO calibration coefficients were determined. The Raman spectrum of the exhaled air was measured and the δC change (in the process of the urea breath test) was calculated. The total error measured was 6% and does not exceed the limit of 10% that was analytically calculated.
Topics: Humans; Helicobacter Infections; Urea; Spectrum Analysis, Raman; Helicobacter pylori; Carbon Dioxide; Breath Tests; Carbon Isotopes; Sensitivity and Specificity
PubMed: 37366973
DOI: 10.3390/bios13060609 -
Tropical Gastroenterology : Official... 2004Helicobacter pylori (H. pylori) is the commonest bacterial pathogen found worldwide and more than half the world population aged 40 years and above is colonized with it.... (Review)
Review
Helicobacter pylori (H. pylori) is the commonest bacterial pathogen found worldwide and more than half the world population aged 40 years and above is colonized with it. The infection rate is >95 % in some African countries. In 1994, the International Agency for Research on cancer classified H. pylori as a class I carcinogen in humans. It causes chronic active gastritis, duodenal and gastric ulcer and gastric malignancy, and is thought to be associated with coronary artery disease, cerebral stroke, vitamin B12 and iron-deficiency anaemia, etc. Therefore, non-invasive test-and-treatment strategies are widely recommended in primary care settings. Conventionally, H. pylori infection can be diagnosed by invasive techniques using an upper gastrointestinal endoscope for obtaining multiple biopsies from different sites of the stomach for RUT, culture, histological examination, polymerase chain reaction (PCR), etc. and by non-invasive tests such as Urea breath test (UBT), stool antigen test and blood serology. At present, 13/14C-UBT is considered the test of choice for confirmation of H. pylori infection. The UBT is based on the principle, that isotopically labelled urea ingested by an H. pylori--infected patient is rapidly hydrolysed by the microbial urease. The released 13/14CO2 is absorbed across the mucous layer to the gastric mucosa and hence, excreted via the systemic circulation in the breath which is collected and measured. The non-hydrolysed urea is excreted completely in the urine within 3-4 days. 13C-UBT being non-radioactive, 13C-UBT can be used in pregnant women and children, and a user's license is not required. There is still no standard protocol accepted and followed internationally for this test. Although the methods are almost similar, various laboratories/clinics use variable tracer doses, test meals, timings and methods for breath collection, and different cut-off values, which make formal validation studies necessary. This review describes the present status of the UBT and its application in the detection of H. pylori infection.
Topics: Breath Tests; Helicobacter Infections; Helicobacter pylori; Humans; Reproducibility of Results; Urea
PubMed: 15912972
DOI: No ID Found