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In this report, we present a post hoc analysis from two observational cohorts, comparing the global breath volatile profile captured when using polymer sampling bags (mixed breath) versus Bio-VOC™ (alveolar breath). The cohorts were originally designed to characterize the breath volatile profiles of Malawian children with and without uncomplicated falciparum malaria. Children aged 3–15 years were recruited from ambulatory pediatric centers in Lilongwe, Malawi. Breath sampling was carried out two months apart (one study using a Bio-VOC™ and the second using sampling bags), and all samples were analyzed by gas chromatography/mass spectrometry. The efficacy of breath collection was assessed by quantifying levels of two high prevalence breath compounds, acetone and isoprene, as well as determining the overall number of breath compounds collected and their abundance. We found that the mean number of volatiles detected using sampling bags was substantially higher than when using the Bio-VOC™ (137 vs. 47). Breath collection by Bio-VOC™ also yielded reduced levels of endogenous breath volatiles, isoprene and acetone, even after breath volume correction. This suggests that the Bio-VOC™ dilutes the volatiles and introduces dead air or ambient air. Our results suggest that sampling bags are better suited for biomarker discovery and untargeted search of volatiles in pediatric populations, as evidenced by superior breath volatile detection.

Background Asthma and COPD continue to cause considerable diagnostic and treatment stratification challenges. Volatile organic compounds (VOCs) have been proposed as feasible diagnostic and monitoring biomarkers in airway diseases. Aims To 1) conduct a systematic review evaluating the diagnostic accuracy of VOCs in diagnosing airway diseases; 2) understand the relationship between reported VOCs and biomarkers of type-2 inflammation; 3) assess the standardisation of reporting according to STARD and TRIPOD criteria; 4) review current methods of breath sampling and analysis. Methods A PRISMA-oriented systematic search was conducted (January 1997 to December 2020). Search terms included: “asthma”, “volatile organic compound(s)”, “VOC” and “COPD”. Two independent reviewers examined the extracted titles against review objectives. Results 44 full-text papers were included; 40/44 studies were cross-sectional and four studies were interventional in design; 17/44 studies used sensor-array technologies (e.g. eNose). Cross-study comparison was not possible across identified studies due to the heterogeneity in design. The commonest airway diseases differentiating VOCs belonged to carbonyl-containing classes (i.e. aldehydes, esters and ketones) and hydrocarbons (i.e. alkanes and alkenes). Although individual markers that are associated with clinical biomarkers of type-2 inflammation were recognised (i.e. ethane and 3,7-dimethylnonane for asthma and α-methylstyrene and decane for COPD), these were not consistently identified across studies. Only 3/44 reported following STARD or TRIPOD criteria for diagnostic accuracy and multivariate reporting, respectively. Conclusions Breath VOCs show promise as diagnostic biomarkers of airway diseases and for type-2 inflammation profiling. However, future studies should focus on transparent reporting of diagnostic accuracy and multivariate models and continue to focus on chemical identification of volatile metabolites., VOCs show promise as noninvasive biomarkers for airway disease diagnosis, anchored to biomarkers of type-2 inflammation https://bit.ly/3utL3sx

Introduction Investigating acute multifactorial undifferentiated breathlessness and understanding the driving inflammatory processes can be technically challenging in both adults and children. Being able to validate noninvasive methods such as breath analysis would be a huge clinical advance. The ReCIVA® device allows breath samples to be collected directly onto sorbent tubes at the bedside for analysis of exhaled volatile organic compounds (eVOCs). We aimed to assess the feasibility of using this device in acutely breathless patients. Methods Adults hospitalised with acute breathlessness and children aged 5–16 years with acute asthma or chronic stable asthma, as well as healthy adult and child volunteers, were recruited. Breath samples were collected onto sorbent tubes using the ReCIVA® device and sent for analysis by means of two-dimensional gas chromatography-mass spectrometry (GCxGC-MS). The NASA Task Load Index (NASA-TLX) was used to assess the perceived task workload of undertaking sampling from the patient's perspective. Results Data were available for 65 adults and 61 children recruited. In total, 98.4% of adults and 75.4% of children were able to provide the full target breath sample using the ReCIVA® device. NASA-TLX measurements were available in the adult population with mean values of 3.37 for effort, 2.34 for frustration, 3.8 for mental demand, 2.8 for performance, 3.9 for physical demand and 2.8 for temporal demand. Discussion This feasibility study demonstrates it is possible and acceptable to collect breath samples from both adults and children at the bedside for breathomics analysis using the ReCIVA® device., It is feasible to collect breath samples for breath analysis at the bedside using the ReCIVA device in acutely breathless adults and children https://bit.ly/2ZTonWo

Modern work environment is changing from classic physiological to more psychological workloads. The capability to monitor biochemical processes within the human body positions breath analysis as a promising method to non-invasively and quickly detect mental stress. The present work aims to identify psychological stress biomarkers and breath profile changes after psychological interventions (PASAT or relaxing videos). In an exploratory study, 14 male participants followed a double cross-over randomized study which included two experimental sessions (stress and neutral/relax). GSR and HR were continuously measured to indicate physiological stress levels. NASA-TLX questionnaires were fulfilled to quantify individual stress. Breath samples were selectively collected by a recently developed advanced breath sampling prototype device and afterwards analyzed with a GC-IMS apparatus. Some promising results on mental stress detection were found and are presented and discussed in this paper.

In parallel to the advances made by the human breath analysis community, significant research has also developed an understanding of breath biomarkers in marine mammals. Several different breath sampling methods have been developed, and these approaches can be used to assess animal health in both wild free-ranging animals and those under managed human care. These methods are summarized in this chapter, and differences between the sampling methods are highlighted and critiqued. A commentary on significant breath biomarkers that have been elucidated in the published literature is provided. Future research trends are also presented for this small yet important research community.

Novel diagnostics have much promise, but they can be difficult to develop from concept to clinical utility. Herein, we review concepts germane to breath research, including metabolite selection and development vision, and offer some practical guidance. Although breath sampling is safe and can inexpensively and quickly deliver measurement results, clinical research evaluating breath analysis must adhere to the same safety and efficacy standards as other forms of clinical trials. A cohesive and well-resourced multidisciplinary team is required. Convincing results are expensive and time consuming to obtain, but essential for clinical, and ultimately, commercial success.

In lung cancer, the prognosis and treatment options depend directly on tumor size and its spread at the time of diagnosis. There is therefore a constant search for methods that will allow early detection of cancerous lung nodules. With advancing imaging technology and implantation of screening routines in high-risk populations by low-dose computerized tomography, a significant increase in the number of diagnosed small peripheral lesions can be expected. While early detection of small cancerous lesions carries the benefit of wider treatment options and better prognosis, the process of obtaining a biopsy to confirm a cancerous tissue is not free of complications and bears inconveniences and stress to the patient. This review discusses the potential use of exhaled breath analysis as a simple, noninvasive tool for early detection of lung cancer and characterization of suspicious lung nodules.

Background & Aims: 13 C-Urea Breath Test (UBT) is a non-invasive, highly accurate and recommended test to detect Helicobacter pylori (H. pylori) infection and to confirm post-therapy eradication. However, differences exist in terms of manufacturers, dose of labelled urea, addition of citric acid, solid vs. liquid formulation, and sampling times of breath samples. In this study, we compared the diagnostic accuracy of “short” (15 minutes) vs. “standard” (30 minutes) time for a single type of liquid UBT. Methods: We compared the performance of a single UBT type (BREATHQUALITY, AB Analitica, Padua, Italy, 10 mL of 75 mg 13 C-Urea and 1.4 g citric acid) during a “short” vs. “standard” breath sampling time. Enrolled were 151 subjects requiring UBT as naïve (N=92) or post-eradication (N=59) checks. Results: UBT at 15 and 30 minutes were highly comparable, showing optimal correlation in all subsets of patients (i.e. naïve vs. post eradication, negative vs. post eradication check). One discrepant result occurred at the borderline zone of the DOB 4‰, but proved to be true positive at a later confirmation by a second UBT and stool antigen test. Conclusions: By shortening the testing time of BREATHQUALITY to 15 minutes (-50%) comparable accuracy will be maintained and in addition, it will bring some benefits to patients’ waiting lists, compliance, and hospital staff.

Objective: Driving under the influence of psychoactive drugs causes an increased risk for accidents. In combating this, sobriety tests at the roadside are common practice in most countries. Sampling of blood and urine for forensic investigation cannot be done at the roadside and poses practical problems associated with costs and time. An alternative specimen for roadside testing is therefore warranted and the aerosol particles in exhaled breath are one such alternative. Methods: The present study investigated how the exhaled breath sample compared with the routine legal investigations of blood and urine collected from suspects of drugged driving at 2 locations in Sweden. Exhaled breath was collected using a simple filter collection device and analyzed with state-of-the-art mass spectrometry technique. Results: The total number of cases used for this investigation was 67. In 54 of these cases (81%) the results regarding a positive or negative drug test result agreed and in 13 they disagreed. Out of these, the report from the forensic investigation of blood/urine was negative in 21 cases. In 6 of these, analytical findings were made in exhaled breath and these cases were dominated by the detection of amphetamine. In 7 cases a positive drug test from the forensic investigation was not observed in the breath sample and these cases were dominated by detection of tetrahydrocannabinol in blood. In total, 45 samples were positive with breath testing and the number of positives with established forensic methods was 46. Conclusion: The promising results from this study provide support to exhaled breath as a viable specimen for testing of drugged driving. The rapid, easy, and convenient sampling procedure offers the possibility to collect a drug test specimen at the roadside. The analytical investigation must be done in a laboratory at present because of the need for a highly sensitive instrument, which is already in use in forensic laboratories. The analytical work is not more challenging than for blood or oral fluid and should not cause an increase in cost. However, more studies need to be done before exhaled breath drug testing can be applied routinely for drugged driving investigation.

This review considers exhaled breath analysis, a non-invasive, widely applicable and cost-effective technique that holds great potential for evolving into a future screening tool for lung cancer and other diseases. Exhaled human breath contains thousands of volatile and non-volatile chemical compounds, which are products of metabolic processes and subject to changes in composition and concentration as a result of carcinogenesis. In the last decade, the analysis of volatile organic compounds (VOCs) has gained increasing interest because of the development of new technologies that might allow for detection of certain VOC biomarkers or patterns indicative of lung cancer. We provide an overview of the chemical analytical and sensor array technologies currently available for VOC analysis, including statistical methods implemented for the analysis of complex VOC patterns, and discuss issues of exhaled breath sampling and storage. Furthermore, we summarize the literature on exhaled breath analysis in lung cancer and discuss the results, limitations and future perspectives. We also briefly review the literature on sniffer dogs trained to detect lung cancer from human breath samples. In conclusion, even though certain issues have yet to be addressed and large randomized blinded studies are still lacking, there is evidence that exhaled breath analysis may be a promising tool for lung cancer screening.

Introduction: Diagnosing asthma in children is challenging and no gold standard diagnostic test exists. Novel non-invasive breath analysis approaches could assist in diagnosis and phenotyping of children with asthma. In the EMBER clinical trial, a ReCIVA breath sampling device was used for bedside breath collection to carry out advanced metabolomics studies. Our aim was to evaluate the feasibility of this breath sampling technology in children. Methods: Samples were taken from children attending hospital with either an acute exacerbation of asthma or stable chronic asthma, and healthy controls. They breathed into the ReCIVA sampler tidally for a maximum of 900s. Two samples were collected for each subject on thermal desorption tubes for analysis by gas chromatography-mass spectrometry. A percentage of breath collected was calculated for each child. For each breath sample, two other samples were collected to capture the environmental air and ReCIVA air supply profiles, necessary for the background subtraction process to identify true breath related endogenous compounds. Results: 51 children participated with a mean age of 11yr (range 5-16). 12 had an acute exacerbation of asthma, 30 had stable chronic asthma and 9 were controls. All tolerated the sampling process and 80% provided 100% of the target breath sampling collection. Discussion: Non-invasive breath analysis in children of varying age with acute and chronic illnesses is feasible. Ongoing work includes a) continuing the analysis of samples and b) following metabolomics data workflow to create a breath matrix. Statistical analysis will allow us to extract target biomarkers with the ultimate aim of improving asthma diagnosis and phenotyping in children.

Introduction Gastrointestinal (GI) cancers are a major cause of morbidity and mortality, yet symptoms are common and non-specific. A non-invasive breath test may be a useful tool for triaging for endoscopy/CT those without red-flag symptoms, or possibly for screening. Prior studies have shown promising results of a breath test for oesophagogastric (80% sensitivity/81% specificity) and colorectal (96% sensitivity/76% specificity) cancers. The Breath MAGIC (Models for Assessment of GI Cancer) study investigates feasibility and acceptability of breath testing in Primary Care. We also developed a quality control (QC) system for breath sampling. Methods This is an prospective cohort study of patients attending their GP for current/recent GI symptoms, from November 2016-May 2017, recruitment target 500. Exhaled breath (250mls) was collected by GP practice/NIHR research nurses using the ReCIVA breath sampling device, onto thermal desorption tubes. Breath volatile organic compounds (VOCs) were analysed using Gas Chromatography (GC) and Proton Transfer Reaction (PTR) Mass Spectrometry, at St Mary’s Hospital VOC laboratory. This platform allows analysis of 100 samples per day of continuous, unattended operation. Patients were recruited from 16 London GP practices on the day or were prebooked via phone/text. Feasibility and acceptability were measured using field notes, a telephone conference then focus group of research nurses (thematicially analysed), and GP questionnaires. To develop a QC system, 76 ‘good quality’ samples taken by one experienced operator were used as a standard. Results Plan-Do-Study-Act cycles from field notes identified barriers and drove regular improvements e.g. phone/text recruitment, a GP poster, grouping of nearby practices, and training healthcare assistants to breath-test. In total 636 patients were enrolled, suggesting breath testing is feasible in Primary Care. Sampling was feasible, with some equipment-related but few patient-related limiting factors reported. Analysis was also feasible, with 34% and 55% of samples analysed within 50 ppb (H3O+ionisation, PTR) and isoprene >2.5 ppb (NO +ionisation, PTR). This was validated on 284 separate patients’ samples. A process was also developed to interrogate ReCIVA software sampling data. Conclusions Breath testing is feasible in Primary Care, from a human factors and process perspective. This finding, and the development of a QC process, opens up the possibility of large-scale breath testing, pending results of diagnostic accuracy studies. A revised recruitment target of 1000 with new patient acceptability questionniares will likely provide further evidence for this.

Background Detecting volatile organic compounds (VOCs) could provide a rapid, noninvasive, and inexpensive screening tool for detecting cancer. Objective In this systematic review, we identified specific exhaled breath VOCs correlated with lung, colorectal, and breast cancer. Methods We identified relevant studies published in 2015 and 2016 by searching Pubmed and Web of Science. The protocol for this systematic review was registered in PROSPERO and the PRISMA guidelines were used in reporting. VOCs and performance data were extracted. Results Three hundred and thirty three records were identified and 43 papers were included in the review, of which 20 were review articles themselves. We identified 17 studies that listed the VOCs with at least a subset of statistics on detection cutoff levels, sensitivity, specificity, area under the receiver operating characteristic curve (AUC), and gradient. Conclusions Breath analysis for cancer screening and early detection shows promise, because samples can be collected easily, safely, and frequently. While gas chromatography-mass spectrometry is considered the gold standard for identifying specific VOCs, breath analysis has moved into analyzing patterns of VOCs using a variety of different multiple sensor techniques, such as eNoses and nanomaterials. Further development of VOCs for early cancer detection requires clinical trials with standardized breath sampling methods.

Background The potential of exhaled breath sampling and analysis has long attracted interest in the areas of medical diagnosis and disease monitoring. This interest is attributed to its non-invasive nature, access to an unlimited sample supply (i.e., breath), and the potential to facilitate a rapid at patient diagnosis. However, progress from laboratory setting to routine clinical practice has been slow. Different methodologies of breath sampling, and the consequent difficulty in comparing and combining data, are considered to be a major contributor to this. To fulfil the potential of breath analysis within clinical and pre-clinical medicine, standardisation of some approaches to breath sampling and analysis will be beneficial. Objectives The aim of this review is to investigate the heterogeneity of breath sampling methods by performing an in depth bibliometric search to identify the current state of art in the area. In addition, the review will discuss and critique various breath sampling methods for off-line breath analysis. Methods Literature search was carried out in databases MEDLINE, BIOSIS, EMBASE, INSPEC, COMPENDEX, PQSCITECH, and SCISEARCH using the STN platform which delivers peer-reviewed articles. Keywords searched for include breath, sampling, collection, pre-concentration, volatile. Forward and reverse search was then performed on initially included articles. The breath collection methodologies of all included articles was subsequently reviewed. Results Sampling methods differs between research groups, for example regarding the portion of breath being targeted. Definition of late expiratory breath varies between studies. Conclusions Breath analysis is an interdisciplinary field of study using clinical, analytical chemistry, data processing, and metabolomics expertise. A move towards standardisation in breath sampling is currently being promoted within the breath research community with a view to harmonising analysis and thereby increasing robustness and inter-laboratory comparisons. Electronic supplementary material The online version of this article (doi:10.1007/s11306-017-1241-8) contains supplementary material, which is available to authorized users.

Breath monitoring is a non-invasive, safe, and repeatable approach to determining the respiratory, gastrointestinal, and general health status of humans and other mammals. Breath samples could be detected in two ways—directly sensing exhaled breath (EB) or chilling the EB to obtaining the exhaled breath condensate (EBC). Each has its advantages and disadvantages but they are both affected by different sampling conditions. The dearth of information on how sampling conditions affect the intrinsic properties of biomarkers in breath hinders the use of breath monitoring in clinical use. In this study, ethanol, a potential biomarker of liver function, was chosen as a model biomarker to demonstrate the effect of sampling conditions on different phases and how breath sampling could be standardized by developing predictive models. EB and EBC samples were determined under three simulated breath temperatures, two breath rates, and two condensing temperatures for developing predictive models. Results showed EB samples were affected by breath temperatures and EBC samples were affected by condensing temperatures. Flow rate changes did not have a significant influence on both EB and EBC samples. Final predictive models based on 5 minute sensing time were developed for EB (R2 = 0.8261) and EBC (R2 = 0.9471).

Exhaled air contains many volatile organic compounds (VOCs) that are the result of normal and disease-associated metabolic processes anywhere in the body. Different omics techniques can assess the pattern of these VOCs. One such omics technique suitable for breath analysis is represented by electronic noses (eNoses), providing fingerprints of the exhaled VOCs, called breathprints. Breathprints have been shown to be altered in different disease states, including in asthma and COPD. This review describes the current status on clinical validation and application of breath analysis by electronic noses in the diagnosis and monitoring of chronic airways diseases. Furthermore, important methodological issues including breath sampling, modulating factors and incompatibility between eNoses are raised and discussed. Next steps towards clinical application of electronic noses are provided, including further validation in suspected disease, assessment of the influence of different comorbidities, the value in longitudinal monitoring of patients with asthma and COPD and the possibility to predict treatment responses. Eventually, a Breath Cloud may be constructed, a large database containing disease-specific breathprints. When collaborative efforts are put into optimization of this technique, it can provide a rapid and non-invasive first line diagnostic test.

Carboxyhaemoglobin (COHb) levels were studied in 11 249 men. The distribution among the 2613 men who smoked cigarettes was well separated from that in 6641 non-smokers (including ex-smokers). The distribution for 2005 cigar and pipe smokers was intermediate, though some of the highest COHb levels occurred in cigar smokers. Using a COHb cut-off level of 2%, 81% of cigarette smokers, 35% of cigar and pipe smokers, and 1.0% of non-smokers had raised COHb levels. In a subsidiary experiment alveolar air samples were collected from 162 smokers and 25 non-smokers using a simple breath sampling technique. Carbon monoxide concentrations in alveolar breath were highly correlated with COHb levels (r = 0.97) indicating that COHb levels can be estimated reliably by measuring the concentration of carbon monoxide in breath. Alveolar carbon monoxide measurement is thus a simple method of estimating whether a person is likely to be a smoker.

There is increasing evidence that breath volatile organic compounds (VOC) have the potential to support the diagnosis and management of inflammatory diseases such as COPD. In this study we used a novel breath sampling device to search for COPD related VOCs. We included a large number of healthy controls and patients with mild to moderate COPD, recruited subjects at two different sites and carefully controlled for smoking. 222 subjects were recruited in Hannover and Marburg, and inhaled cleaned room air before exhaling into a stainless steel reservoir under exhalation flow control. Breath samples (2.5 l) were continuously drawn onto two Tenax(®) TA adsorption tubes and analyzed in Hannover using thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). Data of 134 identified VOCs from 190 subjects (52 healthy non-smokers, 52 COPD ex-smokers, 49 healthy smokers, 37 smokers with COPD) were included into the analysis. Active smokers could be clearly discriminated by higher values for combustion products and smoking related VOCs correlated with exhaled carbon monoxide (CO), indicating the validity of our data. Subjects from the study sites could be discriminated even after exclusion of cleaning related VOCs. Linear discriminant analysis correctly classified 89.4% of COPD patients in the non/ex-smoking group (cross validation (CV): 85.6%), and 82.6% of COPD patients in the actively smoking group (CV: 77.9%). We extensively characterized 134 breath VOCs and provide evidence for 14 COPD related VOCs of which 10 have not been reported before. Our results show that, for the utilization of breath VOCs for diagnosis and disease management of COPD, not only the known effects of smoking but also site specific differences need to be considered. We detected novel COPD related breath VOCs that now need to be tested in longitudinal studies for reproducibility, response to treatment and changes in disease severity.

The analysis of ethanol in exhaled breath is widely used in forensic science and legal medicine as a rapid test for overconsumption of alcohol. The police authorities use breath-alcohol instruments to control sobriety in people suspected of driving under the influence of alcohol. The noninvasive nature of breath sampling offers a definite advantage over drawing blood for analysis of alcohol at a forensic laboratory. Two categories of breath-alcohol instrument are currently in use: hand-held electronic instruments that are used to screen motorists at the roadside and more sophisticated evidential breath analyzers. Results with the latter are accepted by the court when traffic offenders are prosecuted. This article reviews historical development, physiological principles, and practical application of breath-alcohol analysis in forensic science and legal medicine.

Lung cancer diagnosis via breath analysis has to overcome some issues that can be summarized by two crucial points: (1) further developments for more performant breath sampling technologies; (2) discovering more differentiated volatile fingerprints to be ascribed to specific altered biological mechanisms. The present work merges these two aspects in a pilot study, where a breath volume, sampled via endoscopic probe, is analyzed by an array of non-selective gas sensors. Even if the original non-invasive methods of breath analysis has been laid in favour of the endoscopic means, the innovative technique here proposed allows the analysis of the volatile mixtures directly sampled near the tumor mass. This strategy could open the way for a better understanding of the already obtained discrimination among positive and negative cancer cases. The results obtained so far confirm the established discrimination capacity. This allows to discriminate the different subtypes of lung cancer with 75% of correct classification between adenocarcinoma and squamous cell carcinoma. This result suggests that a ‘zoom-in’ on the cancer settled inside the human body can increase the resolution power of key-volatiles detection, allowing the discrimination among different cancer fingerprints. We report this novel technique as a robust support for a better comprehension of the promising results obtained so far and present in literature; it is not to be intended as a replacement for non-invasive breath sampling procedure with the endoscope.

A stable isotope ([(13)C]) breath test is a promising method for assessing gastric emptying, but it has not been pervasive yet in Japan. We think that there are some barriers to its popularization, including the uncertainty concerning its theoretical backgrounds, the ambiguity of analyzing and interpreting the data, and the lack of standard protocols for breath sampling. The aim of the present review is to break through these barriers. We hope this article could make the [(13)C]-gastric breath test more maneuverable for and more accessible to researchers and clinicians.

Background: Exacerbations are an important source of disability, symptoms, loss of quality of life and lung function, and high costs of care in patients with cystic fibrosis (CF). Purpose: the aim was to assess the ability of noninvasive inflammation markers in exhaled breath to predict exacerbations in children with CF. Methods: 49 children with CF aged 5-18 years were prospectively followed during one year. At 2 month-intervals, the following parameters were assessed: 1) lung function (forced expiratory volume in one second [FEV1] and forced vital capacity [FVC]) according to ERS/ATS standards; 2) exhaled breath condensate (EBC) was sampled and TNF-alpha, macrophage inhibiting factor (MIF), interleukin-6 (IL-6) and IL-8 were analysed; 3) 1 liter of exhaled breath was stabilized on carbon desorption tubes, and volatile organic compounds (VOCs) profiles were analyzed by gaschromotography time-of-flight mass spectrometry (GC-TOF-MS); Results: The mean age was 10.3 years, and the mean FEV1 was 89,6% of predicted value. 17 of the 49 patients experienced no exacerbations (=35%) , whereas 32 children got one or more exacerbations. Markers in EBC predicted 55% of the exacerbations correctly (sensitivity 70%, specificity 50%, 9conditionally specified models9). A combination of 9 most predictive VOCs was able to predict 79% of exacerbations correctly (sensitivity 81%, specificity 82%), provided that the time between the exhaled breath sampling and onset of exacerbations was not longer than 1 week. Conclusion: CF exacerbations were best predicted by a set of 9 VOCs in exhaled breath, provided that the time interval between breath sampling and exacerbations was not longer than 7 days.

Background: A crucial issue in the analysis of exhaled breath is the collection of gaseous samples. The analysis of pure alveolar gas is the method of choice if contamination of samples is to be minimized. Monitoring of expired CO_{2} can be used to identify alveolar gas. The purpose of this study was to evaluate a bed side version of this technique using visual CO_{2} control by means of a capnometer. Methods: 22 mechanically ventilated patients of an ICU were enrolled into the study. Alveolar and mixed expiratory gas, and arterial blood were sampled. PCO_{2} in blood and gas was determined in a blood gas analyzer. End tidal PCO_{2} was monitored in all patients by a fast responding main stream capnometry. Taking the gaseous samples was visually synchronized with the expired CO_{2}. Results: Alveolar CO_{2} contents measured during two different respiratory cycles were identical (p 0.86). The variation of the CO_{2} content during 10 measurements in one patient was lower than 4%. Arterial PCO_{2}, PCO_2 in alveolar gas and end tidal PCO_{2} showed positive correlation. Conclusions: The visually CO_{2}-controlled sampling technique of alveolar gas is a reliable and reproducible method. It represents an important step in simplifying and standardizing breath analysis.

The (13)C-urea breath test ((13)C-UBT) is the most accurate non-invasive method for diagnosis of Helicobacter pylori infection. However, several methodological issues have not been resolved yet. The aim of this study was to test different protocols of (13)C-UBT to find the optimal test drink and sampling interval.(13)C-UBT was performed at 3-day intervals in 27 healthy volunteers using citric acid (test A), orange juice (B) and still water (C) as test drinks. Breath samples were collected from time 5 to 60 min. A total number of 2106 breath samples were analysed by isotope ratio mass spectrometry (cut-off value 3.5).Differences in delta values were greater than would be expected by chance (A versus B and A versus C at times 20, 25, 30, 35 and 40 min, p0.05, Dunnett's method). There were no grey zone- or false-negative results among H. pylori-positive persons in test A at any time, but some were found in tests B and C. Optimal intervals for breath sampling are at times 20 or 25 min after (13)C-urea ingestion.Citric acid solution as a test drink and 20- or 25-min breath sampling intervals are optimal for the (13)C-UBT in healthy volunteers.

Breath sampling and analysis provide healthcare professionals with a practical, noninvasive diagnostic measurement for children with a variety of gastrointestinal (GI) disorders. New biomarkers found in human breath have been investigated and provide the opportunity to diagnose bacterial overgrowth and other underlying causes of GI dysfunction. Although several protocols have been described previously regarding breath sampling, few have demonstrated the feasibility of collection in young children. This communication introduces a simple game that allows for 3- to 7-year-old children to practice breath exhalation to give a proper breath sample in a relaxed and comfortable environment. The technique described offers clinicians a creative approach for obtaining breath samples from a child by reducing the apprehension and anxiety associated with the research and clinical environment.

Breath analysis has attracted a considerable amount of scientific and clinical interest during the last decade. In contrast to NO, which is predominantly generated in the bronchial system, volatile organic compounds (VOCs) are mainly blood borne and therefore enable monitoring of different processes in the body. Exhaled ethane and pentane concentrations were elevated in inflammatory diseases. Acetone was linked to dextrose metabolism and lipolysis. Exhaled isoprene concentrations showed correlations with cholesterol biosynthesis. Exhaled levels of sulphur-containing compounds were elevated in liver failure and allograft rejection. Looking at a set of volatile markers may enable recognition and diagnosis of complex diseases such as lung or breast cancer. Due to technical problems of sampling and analysis and a lack of normalization and standardization, huge variations exist between results of different studies. This is among the main reasons why breath analysis could not yet been introduced into clinical practice. This review addresses the basic principles of breath analysis and the diagnostic potential of different volatile breath markers. Analytical procedures, issues concerning biochemistry and exhalation mechanisms of volatile substances, and future developments will be discussed.

Retention of mouth alcohol may result in falsely high breath alcohol concentrations and is thus a concern in evidential breath alcohol testing. Frequent breath sampling used in the typical mouth alcohol experiment may underestimate the duration and magnitude of the mouth alcohol effect in comparison to the real-life forensic situation. On each of three separate trials, nineteen female, and eleven male, alcohol-free subjects rinsed their mouths with 20 mL of diluted vodka (20% alcohol v/v) for 20 seconds and then expectorated. On each of the trials, the subjects provided breath samples into an Intoxilyzer® 5000C either every two minutes, every four minutes, or every eight minutes, respectively. The subjects did not talk or open their mouths throughout the experiment except for providing the breath sample. The final breath result displayed, as well as whether or not the instrument detected mouth alcohol, was recorded. As expected, an increase in the frequency of breath sampling significantly decreas...

Background: In-community non-invasive identification of asthma-specific volatile organic compounds (VOCs) in exhaled breath presents opportunities to characterize phenotypes, and monitor disease state and therapies. The feasibility of breath sampling with children and the preliminary identification of childhood asthma markers were studied. Method: End-tidal exhaled breath was sampled (2.5 dm3) from 11 children with asthma and 12 healthy children with an adaptive breath sampler. VOCs were collected onto a Tenax®/Carbotrap hydrophobic adsorbent trap, and analyzed by GC–MS. Classification was by retention-index and mass spectra in a ‘breath matrix‘ followed by multivariate analysis. Results: A panel of eight candidate markers (1-(methylsulfanyl)propane, ethylbenzene, 1,4-dichlorobenzene, 4-isopropenyl-1-methylcyclohexene, 2-octenal, octadecyne, 1-isopropyl-3-methylbenzene and 1,7-dimethylnaphtalene) were found to differentiate between the asthmatic and healthy children in the test cohort with complete separation by 2D principal components analysis (2D PCA). Furthermore, the breath sampling protocol was found to be acceptable to children and young people. Conclusion: This method was found to be acceptable for children, and healthy and asthmatic individuals were distinguished on the basis of eight VOCs at elevated levels in the breath of asthmatic children.

The *C (13C or 14C) labelled octanoic acid breath test was recently developed to measure the gastric emptying rate of solids. This study aimed to investigate whether it is sensitive enough to detect pharmacologically induced changes in the gastric emptying rate. Nine healthy volunteers were studied in basal condition, after intravenous administration of 200 mg erythromycin, and after peroral administration of 30 mg propantheline. Erythromycin significantly enhanced gastric emptying in all subjects, with an increase of the gastric emptying coefficient (p = 0.0043) in eight of nine and a fall in both the gastric half emptying time (p = 0.0020) and the lag phase (p = 0.0044) in all nine. Propantheline significantly reduced the gastric emptying rate, with a decreased gastric emptying coefficient (p = 0.0007) and an increased gastric half emptying time (p = 0.0168) in all subjects, but no change in the lag phase (p = 0.1214). Further mathematical analysis showed that breath sampling at 15 minutes intervals over a four hour period is recommended to guarantee accuracy and the discriminative value of the breath test in various gastric emptying patterns. In conclusion the *C labelled octanoic acid breath test is sufficiently sensitive to show pharmacologically induced changes of gastric emptying rates of solids.

Breath gas analysis provides insight into human metabolism of healthy and ill individuals. As an innovative and non-invasive method, it opens up options to improve diagnostics, monitoring and treatment decisions. Mid-infrared laser absorption spectroscopy is utilized to detect CH(4), H(2)O, CO(2), NH(3) and CH(3)OH in exhaled human breath. An off-line approach using breath sampling by means of Tedlar bags is applied. The breath gas samples are measured within the population-based epidemiological Study of Health in Pomerania (SHIP-TREND) performed at the University of Greifswald. The study covers about 5000 adult subjects aged 20-79 years within 3 years. Besides breath gas analysis many other examinations are conducted. It is expected to find associations between distinct concentration levels of species in the exhaled breath and diseases assessed in this study. The study will establish reference values for exhaled breath components and serve as background population for case-control studies. In the long run, morbidity and mortality follow-ups will be conducted, which will answer the question whether end-expiratory breath gas components predict future diseases and death. As first results, we present data from 45 dialysis patients (23 males, 22 females) which were recruited in a preliminary study in preparation for SHIP-TREND.

Over the last few years, breath analysis for the routine monitoring of metabolic disorders has attracted a considerable amount of scientific interest, especially since breath sampling is a non-invasive technique, totally painless and agreeable to patients. The investigation of human breath samples with various analytical methods has shown a correlation between the concentration patterns of volatile organic compounds (VOCs) and the occurrence of certain diseases. It has been demonstrated that modern analytical instruments allow the determination of many compounds found in human breath both in normal and anomalous concentrations. The composition of exhaled breath in patients with, for example, lung cancer, inflammatory lung disease, hepatic or renal dysfunction and diabetes contains valuable information. Furthermore, the detection and quantification of oxidative stress, and its monitoring during surgery based on composition of exhaled breath, have made considerable progress. This paper gives an overview of the analytical techniques used for sample collection, preconcentration and analysis of human breath composition. The diagnostic potential of different disease-marking substances in human breath for a selection of diseases and the clinical applications of breath analysis are discussed.

Contains fulltext : 35117.pdf (Publisher’s version ) (Closed access) We present a new, off-line breath collection and analysis method, suitable for large screening studies. The breath collection system is based on the guidelines of the American Thoracic Society for the sampling of exhaled NO. Breath containing volatile gases is collected in custom-made black-layered Tedlar bags and analyzed by proton- transfer reaction mass spectrometry (PTR-MS). The collection method and data analysis is validated for its accuracy, precision, selectivity, limits of detection, sensitivity and reproducibility. Consecutive fillings of five bags by the same person gave reproducible results to within 12% relative standard deviation (RSD) for methanol, acetaldehyde, acetone and water content from breath, whereas isoprene was constant to within 30% RSD. In an exploratory small-scale case-control study, we monitor the exhaled breath of 11 lung cancer patients on the day before surgery. The control group consisted of 57 age-matched subjects, the so-called `healthy smokers'. This study is used as an example of the use of the system presented here.

Objectives & Background Exhaled Volatile Organic Compounds (eVOCs) have been used to identify patients with many diseases including pseudomonas infection and lung cancer. Breath for eVOC analysis is conventionally collected from one or more deep exhalations. The long controlled exhalation of the American Thoracic Association nitric oxide protocol has been the commonest method used in breath research. However, some patients may be unable or unwilling to perform deep exhalations. Movement of breath analysis from the laboratory to the bedside requires a patient-friendly method for collecting breath samples, especially if breath analysis is to be tested in the relatively uncontrolled environment of an Emergency Department. Continuous monitoring of VOC spectra throughout the breath cycle during tidal breathing has the potential to provide an easier method of sample collection in the clinical situation. This study was designed to compare single controlled exhalation with tidal breathing. Methods Exhaled breath volatile organic compounds were measured to compare two methods of breath collection in emergency care; the standard single prolonged exhalation (incentive test) and relaxed breathing (tidal test). 125 patients with minor conditions were recruited from the Emergency Department and samples were collected in real-time using an on-line PTR-ToF-MS coupled to Loccioni breath collection apparatus. A Matlab program was used to extract the spectra of the alveolar portion of breath and measure the abundance of each eVOC. Results The total amount of eVOCs detected by the two methods was highly correlated (R2=0.91), with the incentive method giving slightly higher overall eVOC levels than the tidal breath method (mean of differences=98,749 NCPS, P Conclusion Following this study we recommend the use of a tidal breath sampling method in future studies of emergency care patients to prevent selection bias.

Breath analysis in respiratory disease is a non-invasive technique which has the potential to complement or replace current screening and diagnostic techniques without inconvenience or harm to the patient. Recent advances in ion mobility spectrometry (IMS) have allowed exhaled breath to be analysed rapidly, reliably and robustly thereby facilitating larger studies of exhaled breath profiles in clinical environments. Preliminary studies have demonstrated that volatile organic compound (VOC) breath profiles of people with respiratory disease can be distinguished from healthy control groups but there is a need to validate, standardise and ensure comparability between laboratories before real-time breath analysis becomes a clinical reality. It is also important that breath sampling procedures and methodologies are developed in conjunction with clinicians and the practicalities of working within the clinical setting are considered to allow the full diagnostic potential of these techniques to be realised. A protocol is presented, which has been developed over three years and successfully deployed for quickly and accurately collecting breath samples from 323 respiratory patients recruited from 10 different secondary health care clinics.

This paper presents data from both a human volunteer study looking at exposure to 1,3,5-trimethylbenzene (TMB) and an occupational hygiene study of a printing firm using screen wash containing technical grade TMB. The biomarkers measured were TMB in blood and breath, and urinary dimethylbenzoic acids (DMBAs). The volunteer (N = 4) study showed that TMB was rapidly absorbed into the bloodstream reaching a mean level of 0.85 micromol l(-1) during a 4 h exposure to 25 p.p.m. TMB. There was little decline 1 h post-exposure possibly indicating storage of TMB in adipose tissue. Breath TMB levels peaked within an hour of exposure commencing and averaged 137 nmol l(-1) during exposure. Elimination of TMB in breath was biphasic with an initial half-life of 60 min. Peak excretion of urinary DMBA occurred 4-8 h after the end of exposure and averaged 40 mmol mol(-1) creatinine. Elimination of DMBA in urine was biphasic with half-lives of 13 and 60 h indicating that accumulation of body burden throughout the working week is likely if exposure is repeated. The occupational hygiene study demonstrated an excellent correlation between personal air TMB levels and post-shift urinary DMBA levels (r = 0.997) collected on the third working day. The regression equation from this study indicates that 8 h exposure to 25 p.p.m. TMB would result in a urinary DMBA level of 206 mmol mol(-1) creatinine. All workers showed pre-shift levels of DMBA from exposure to TMB on previous days. Both urinary DMBA and breath TMB levels can be used as biomarkers of TMB exposure. Urine samples should be taken post-shift towards the end of the working week as significant body burden accumulation throughout the working week can be expected. Breath sampling is more suited to task or single-shift monitoring.

As a non-invasive modality by which to evaluate the gastric emptying of a solid meal, the 13C-octanoic acid breath test has recently become more widely used. Previously, we reported that ultrasonography was another non-invasive and reliable method for assessing gastric motility. The aim of this study was to compare the reliability of these two methods.Seventeen patients with functional dyspepsia and 10 healthy volunteers were studied. The solid test meal consisted of a scrambled egg labeled with 13C-octanoic acid (100 mg) and served with a bowl of rice and boiled chicken (total 424 kcal). After ingestion of the test meal, all subjects were examined in the sitting position. Ultrasonography images were obtained every 15 min for 3 h. Breath sampling followed the same time schedule as for the ultrasonography, with an additional 3 h of sampling at 30-min intervals. We investigated the half emptying time (T1/2) and the lag phase with both methods.The T1/2 by the ultrasonography method and the breath test were positively correlated (r2 = 0.638); however, there was no significant agreement between the study groups. Both the T1/2 and the lag phase were prolonged in the functional dyspepsia patients compared with the healthy volunteers, regardless of the method of measurement. The lag phase was significantly correlated (r2=0.864) with the T1/2 by the breath test.Although the 13C-octanoic acid breath test cannot assess the gastric emptying of solids as reliably as ultrasonography, both tests are useful for evaluating functional dyspepsia patients with delayed gastric emptying.

Determination of13CO2enrichment on the CO2 released from blood by acid has been used in situations in which breath sampling is difficult. This method can be improved by measuring this enrichment on the CO2 spontaneously released from blood. Therefore, simultaneous comparisons of13CO2content between breath and arterialized blood added with or without acid were performed in 51 samples from human studies, using the statistical method of Bland and Altman (J. M. Bland and D. G. Altman. Lancet 1: 307–310, 1986). Strong relationships exist between the methods ( r > 0.99) expressed in atom percent excess (APE). Compared with breath, the acid method overestimates the13CO2enrichment (0.318 ± 0.632 APE × 1,000, P < 0.001). The acid-free method shows similar enrichments to breath (0.003 ± 0.522 APE × 1,000, P = 0.97) with good precision and degree of agreement (95% confidence interval 0.15 APE × 1,000). The analysis can be performed up to 5 days after sampling with a good reproducibility. In conclusion, measuring13CO2enrichments on the CO2spontaneously released from blood is feasible, gives identical results to the breath method, and lessens operator manipulations. It allows study of situations in which the breath sampling method is not feasible.

The human volatilome: volatile organic compounds (VOCs) in exhaled breath, skin emanations, urine, feces and saliva Anton Amann, Ben de Lacy Costello, Wolfram Miekisch et al. Cell culture metabolomics in the diagnosis of lung cancer--the influence of cell culture conditions. U Kalluri, M Naiker and M A Myers Simply breath-taking? Developing a strategy for consistent breath sampling J D Beauchamp and J D Pleil The application of statistical methods using VOCs to identify patients with lung cancer Agnieszka Ulanowska, Tomasz Kowalkowski, Ewa Trawiska et al. Breath biomarkers of breast cancer Michael Phillips, Renee N Cataneo, Christobel Saunders et al. An off-line breath sampling and analysis method suitable for large screening studies M M L Steeghs, S M Cristescu, P Munnik et al. Breath analysis—past, present and future: a special issue in honour of Michael Phillips' 70th birthday

The chemical analysis of exhaled breath gas to assess state of health or identify disease biomarkers has gained growing interest in recent years, with advances in new technologies providing scientists and physicians with a powerful analytical arsenal with which to tackle pertinent issues. The application of these methods for pharmacokinetic studies, however, has received less attention despite its enormous potential in this field. For instance, breath gas analysis may be employed to characterize uptake and distribution within the body of exogenous volatile compounds, either from a pharmaceutical point of view, or in relation to environmental inhalation exposure. Both of these topics can benefit greatly from utilizing breath gas complementarily or as a surrogate to blood as an analytical medium, since breath sampling is non-invasive, inexhaustible, and is achievable with a frequency far exceeding that which is feasible for blood. However, because of the efficiency with w hich certain exogenous compounds are reflected in breath, this can also often be a significant source of confounding variables that require consideration in routine breath gas analyses. This paper provides an overview of the possibilities of breath gas analysis for pharmacokinetics and environmental exposure investigations and discusses the presence of exogenous compounds in standard breath analyses and their repercussions in terms of erroneous data interpretation.

The history of breath alcohol analysis and of the concept of a blood: breath ratio is briefly reviewed and it is suggested that the ratio is always lower and more variable than predicted by accepted theory. Using gas liquid chromatography for both breath and blood it has been shown that the blood: breath ratio falls during expiration and only reaches its presently accepted value of 2100: 1, predicted from in vitro studies, after prolonged rebreathing. It is suggested that this is due to alcohol being absorbed from the breath during expiration by the mucosa of the upper respiratory tract, to replace that lost during inspiration. Proposals are made for further studies and for modifications in present breath sampling procedures which could make breath analysis an acceptable substitute for blood analysis in all except marginal cases.

An accurate, relatively simple gas-solid chromatographic method for determination of breath H2 is described. Three different end-expiratory breath sampling techniques were evaluated. Changes in ventilatory activity was found to be the main cause of inaccuracies in end-expiratory breath H2 determinations. Pulmonary H2 excretion was measured after instillations of H2 in jejunum and colon. H2 excretion during the first 30 min after instillation was approximately seven times greater from the jejunum than from the colon. Marked individual variability was noted, and it is suggested that this may be explained by variations in intestinal peristaltic activity, which must be of importance in the process of H2 diffusion from gut lumen. It is further suggested that the H2 breath test should be regarded as a semi-quantitative test for intestinal H2 formation.

Production of hydrogen (H2) was simultaneously estimated by both end-tidal breath sampling (ETH2) and by direct excretion rate determinations (VeH2), using a flow-through system with gastight head hood and reduction gas detector (res. = .010 ppm/2.5 ml sample). Studies were performed on 8 normal formula-fed infants of various postnatal and gestational ages immediately after feeding with sampling at 30-minute intervals until the next feeding (2-3 hrs). Linear regression analysis of the normalized data showed no significant elevation in H2 production over the first 1, 2, or 3 hrs after feeding. ETH2 and VeH2 for each infant were thus taken to be the respective means of the multiple separate determinations during the sampling period. For the infant studies with complete data (n=10), mean ETH2 was 31±24.9 (S.D.) ppm (range 6.85 to 90.6 ppm); mean VeH2 was 1.47±.89 (S.D.)ml/hr (range .18 to 2.96 ml/hr). The failure of feeding to elicit an increase in either ETH2 or VeH2 and the persistence of high values relative to adult levels may be contributed to by the continuous presence of carbohydrate substrate in the gut because of frequent feeding. This hypothesis is supported by data from one extended study (5 hrs) during which no increase in ETH2 was noted after feeding, but a drop to 50% of the initial mean value occurred after 3 hours (r = .87).