Urinary Volatile Organic Compound Analysis Research Articles

Discrimination of Diabetes Mellitus Patients and Healthy Individuals Based on Volatile Organic Compounds (VOCs): Analysis of Exhaled Breath and Urine Samples by Using E-Nose and VE-Tongue

Studies suggest that breath and urine analysis can be viable non-invasive methods for diabetes management, with the potential for disease diagnosis. In the present work, we employed two sensing strategies. The first strategy involved analyzing volatile organic compounds (VOCs) in biological matrices, such as exhaled breath and urine samples collected from patients with diabetes mellitus (DM) and healthy controls (HC). The second strategy focused on discriminating between two types of DM, related to type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM), by using a data fusion method. For this purpose, an electronic nose (e-nose) based on five tin oxide (SnO2) gas sensors was employed to characterize the overall composition of the collected breath samples. Furthermore, a voltametric electronic tongue (VE-tongue), composed of five working electrodes, was dedicated to the analysis of urinary VOCs using cyclic voltammetry as a measurement technique. To evaluate the diagnostic performance of the electronic sensing systems, algorithm tools including principal component analysis (PCA), discriminant function analysis (DFA) and receiver operating characteristics (ROC) were utilized. The results showed that the e-nose and VE-tongue could discriminate between breath and urine samples from patients with DM and HC with a success rate of 99.44% and 99.16%, respectively. However, discrimination between T1DM and T2DM samples using these systems alone was not perfect. Therefore, a data fusion method was proposed as a goal to overcome this shortcoming. The fusing of data from the two instruments resulted in an enhanced success rate of classification (i.e., 93.75% for the recognition of T1DM and T2DM).

Development of a headspace-solid phase microextraction gas chromatography-high resolution mass spectrometry method for analyzing volatile organic compounds in urine: Application in breast cancer biomarker discovery

Background and aimBreast cancer (BC) is the leading cause of cancer-related death in females. The development of non-invasive methods for the early diagnosis of BC still remains challenge. Here, we aimed to discover the urinary volatile organic compounds (VOCs) pattern of BC patients and identify potential VOC biomarkers for BC diagnosis. MethodsUrine samples were analyzed by headspace-solid phase microextraction (HS-SPME) combined with gas chromatography-high resolution mass spectrometry (GC-HRMS). To assure reliable analysis, the factors influencing HS-SPME extraction efficiency were comprehensively investigated and optimized by combing the Plackett–Burman design (PBD) with the central composite design (CCD). The established HS-SPME/GC-HRMS method was validated and applied to analyze urine samples from BC patients (n = 80) and healthy controls (n = 88). ResultsA total number of 134 VOCs belonging to distinct chemical classes were identified by GC-HRMS. BC patients demonstrated unique urinary VOCs pattern. Orthogonal partial least squares-discriminant analysis (OPLS-DA) showed a clear separation between BC patients and healthy controls. Eight potential VOC biomarkers were identified using multivariate and univariate statistical analysis. The predictive ability of candidate VOC biomarkers was further investigated by the random forest (RF) algorithm. The candidate VOC biomarkers yielded 76.3% sensitivity and 85.4% specificity on the training set, and achieved 76.0% sensitivity and 92.3% specificity on the validation set. ConclusionsOverall, this work not only established a standardized HS-SPME/GC-HRMS approach for urinary VOCs analysis, but also highlighted the value of urinary VOCs for BC diagnosis. The knowledge gained from this study paves the way for early diagnosis of BC using urine in a non-invasive manner.

Detection of spontaneous preterm birth by maternal urinary volatile organic compound analysis: A prospective cohort study.

Accurate prediction of preterm birth is currently challenging, resulting in unnecessary maternal hospital admittance and fetal overexposure to antenatal corticosteroids. Novel biomarkers like volatile organic compounds (VOCs) hold potential for predictive, bed-side clinical applicability. In a proof of principle study, we aimed to assess the predictive potential of urinary volatile organic compounds in the identification of pregnant women at risk for preterm birth. Urine samples of women with a high risk for preterm birth (≧24 + 0 until 36 + 6 weeks) were collected prospectively and analyzed for VOCs using gas chromatography coupled with an ion mobility spectrometer (GS-IMS). Urinary VOCs of women delivering preterm were compared with urine samples of women with suspicion of preterm birth collected at the same gestation period but delivering at term. Additionally, the results were also interpreted in combination with patient characteristics, such as physical examination at admission, microbial cultures, and placental pathology. In our cohort, we found that urinary VOCs of women admitted for imminent preterm birth were not significantly different in the overall group of women delivering preterm vs. term. However, urinary VOCs of women admitted for imminent preterm birth and delivering between 28 + 0 until 36 + 6 weeks compared to women with a high risk for preterm birth during the same gestation period and eventually delivering at term (>37 + 0 weeks) differed significantly (area under the curve: 0.70). In addition, based on the same urinary VOCs, we could identify women with a confirmed chorioamnionitis (area under the curve: 0.72) and urinary tract infection (area under the curve: 0.97). In conclusion, urinary VOCs hold potential for non-invasive, bedside prediction of preterm birth and on the spot identification of intra-uterine infection and urinary tract infections. We suggest these observations are further explored in larger populations.

Comparative analysis of volatile organic compounds of breath and urine for distinguishing patients with liver cirrhosis from healthy controls by using electronic nose and voltammetric electronic tongue

Advanced stage detection of liver cirrhosis (LCi) would lead to high mortality rates in patients. Therefore, accurate and non-invasive tools for its early detection are highly needed using human emanations that may reflect this disease. Human breath, along with urine and blood, has long been one of the three main biological media for assessing human health and environmental exposure. The primary objective of this study was to explore the potential of using volatile organic compounds (VOCs) assay of exhaled breath and urine samples for the diagnosis of patients with LCi and healthy controls (HC). For this purpose, we used a hybrid electronic nose (E-nose) combining two sensor families, consisting of an array of five commercial chemical gas sensors and six interdigitated chemical gas sensors based on pristine or metal-doped WO3 nanowires for sensing volatile gases in exhaled breath. A voltammetric electronic tongue (VE-tongue), composed of five working electrodes, was dedicated to the analysis of urinary VOCs using cyclic voltammetry as a measurement technique. 54 patients were recruited for this study, comprising 22 patients with LCi, and 32 HC. The two-sensing systems coupled with pattern recognition methods, namely Principal Component Analysis (PCA) and Discriminant Function Analysis (DFA), were trained to classify data clusters associated with the health status of the two groups. The diagnostic performances of the E-nose and VE-tongue systems were studied by using the receiver operating characteristic (ROC) method. The use of the E-nose or the VE-tongue separately, trained with these appropriate classifiers, showed a slight overlap indicating no clear discrimination between LCi patients and HC. To improve the performance of both electronic sensing devices, an emerging strategy, namely a multi-sensor data fusion technique, was proposed as a second aim to overcome this shortcoming. The data fusion approach of the two systems, at a medium level of abstraction, has demonstrated the ability to assess human health and disease status using non-invasive screening tools based on exhaled breath and urinary VOC analysis. This suggests that exhaled breath as well as urinary VOCs are specific to a disease state and could potentially be used as diagnostic methods.

Exploratory Study Using Urinary Volatile Organic Compounds for the Detection of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) biomarkers are lacking in clinical practice. We therefore explored the pattern and composition of urinary volatile organic compounds (VOCs) in HCC patients. This was done in order to assess the feasibility of a potential non-invasive test for HCC, and to enhance our understanding of the disease. This pilot study recruited 58 participants, of whom 20 were HCC cases and 38 were non-HCC cases. The non-HCC cases included healthy individuals and patients with various stages of non-alcoholic fatty liver disease (NAFLD), including those with and without fibrosis. Urine was analysed using gas chromatography–ion mobility spectrometry (GC–IMS) and gas chromatography–time-of-flight mass spectrometry (GC–TOF-MS). GC–IMS was able to separate HCC from fibrotic cases with an area under the curve (AUC) of 0.97 (0.91–1.00), and from non-fibrotic cases with an AUC of 0.62 (0.48–0.76). For GC-TOF-MS, a subset of samples was analysed in which seven chemicals were identified and tentatively linked with HCC. These include 4-methyl-2,4-bis(p-hydroxyphenyl)pent-1-ene (2TMS derivative), 2-butanone, 2-hexanone, benzene, 1-ethyl-2-methyl-, 3-butene-1,2-diol, 1-(2-furanyl)-, bicyclo(4.1.0)heptane, 3,7,7-trimethyl-, [1S-(1a,3β,6a)]-, and sulpiride. Urinary VOC analysis using both GC–IMS and GC-TOF-MS proved to be a feasible method of identifying HCC cases, and was also able to enhance our understanding of HCC pathogenesis.

Urinary Volatile Organic Compound Analysis for the Diagnosis of Cancer: A Systematic Literature Review and Quality Assessment.

The analysis of urinary volatile organic compounds (VOCs) is a promising field of research with the potential to discover new biomarkers for cancer early detection. This systematic review aims to summarise the published literature concerning cancer-associated urinary VOCs. A systematic online literature search was conducted to identify studies reporting urinary VOC biomarkers of cancers in accordance with the recommendations of the Cochrane Library and Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines. Thirteen studies comprising 1266 participants in total were included in the review. Studies reported urinary VOC profiles of five cancer subtypes: prostate cancer, gastrointestinal cancer, leukaemia/lymphoma, lung cancer, and bladder cancer. Forty-eight urinary VOCs belonging to eleven chemical classes were identified with high diagnostic performance. VOC profiles were distinctive for each cancer type with limited cross-over. The metabolic analysis suggested distinctive phenotypes for prostate and gastrointestinal cancers. The heterogenicity of study design, methodological and reporting quality may have contributed to inconsistencies between studies. Urinary VOC analysis has shown promising performance for non-invasive diagnosis of cancer. However, limitations in study design have resulted in inconsistencies between studies. These limitations are summarised and discussed in order to support future studies.

Differentiating cancer types using a urine test for volatile organic compounds

Background. In the human body, volatile organic compounds (VOCs) are produced by different tissues then secreted in different body fluids and subsequently excreted. Here we explore a non-invasive method for the detection of liver, prostate and bladder cancers. Methods. We recruited 140 cases. There were 31 hepatocellular carcinomas (HCC), 62 prostate carcinomas, 29 bladder carcinomas and 18 non-cancer cases. Male to female ratio was 5:1 and mean age was 72 years. Urinary VOCs were detected by applying solid-phase microextraction (SPME) technique. Results. The sensitivity for detection of HCC with normal alpha fetoprotein (AFP) was 68% (SE 0.06, 95% CI 0.54 to 0.81 and P < 0.005). The VOCs sensitivity in the detection of HCC cases with raised AFP was 83%. (SE 0.05, 95% CI 0.73 to 0.93 and P < 0.0001). The VOCs sensitivity for prostate cancer detection was 70% (SE 0.049, 95% CI 0.60 to 0.79 and P < 0.0002) and sensitivity for bladder cancer detection was 81% (SE 0.052, 95% CI 0.70 to 0.91 and P < 0.0001). Conclusions. SPME urinary VOCs analysis was able to differentiate between controls and each of hepatocellular, prostate and bladder cancers. This suggests that urinary VOCs are cancer specific and could potentially be used as a diagnostic method.

Smell - Adding a New Dimension to Urinalysis.

Background: Urinary tract infections (UTI) are among the most common infections in children. The primary tool to detect UTI is dipstick urinalysis; however, this has limited sensitivity and specificity. Therefore, urine culture has to be performed to confirm a UTI. Urinary volatile organic compounds (VOC) may serve as potential biomarker for diagnosing UTI. Previous studies on urinary VOCs focused on detection of UTI in a general population; therefore, this proof-of-principle study was set up in a clinical high-risk pediatric population. Methods: This study was performed at a tertiary nephro-urological clinic. Patients included were 0–18 years, clinically suspected of a UTI, and had abnormal urinalysis. Urine samples were divided into four groups, i.e., urine without bacterial growth, contamination, colonization, and UTI. VOC analysis was performed using an electronic nose (eNose) (Cyranose 320®) and VOC profiles of subgroups were compared. Results: Urinary VOC analysis discriminated between UTI and non-UTI samples (AUC 0.70; p = 0.048; sensitivity 0.67, specificity 0.70). The diagnostic accuracy of VOCs improved when comparing urine without bacterial growth versus with UTI (AUC 0.80; p = 0.009, sensitivity 0.79, specificity 0.75). Conclusions: In an intention-to-diagnose high-risk pediatric population, UTI could be discriminated from non-UTI by VOC profiling, using an eNose. Since eNose can be used as bed-side test, these results suggest that urinary VOC analysis may serve as an adjuvant in the diagnostic work-up of UTI in children.

Urinary volatilome analysis in a mouse model of anxiety and depression.

Psychiatric disorders including depression and anxiety comprise a broad range of conditions with different symptoms. We have developed a mouse model of depression/anxiety in mice deficient in the St3gal4 gene. In this study, we performed a comparative analysis of urinary volatile organic compounds (VOCs) in St3gal4-deficient (St3gal4-KO) and wild-type mice using gas chromatography-mass spectrometry, and we screened 18 putative VOCs. Principal component analysis (PCA) based on these VOCs identified a major group of 11 VOCs, from which two groups were clarified by hierarchical clustering analysis. One group including six VOCs (pentanoic acid, 4-methyl-, ethyl ester; 3-heptanone, 6-methyl; benzaldehyde; 5,9-undecadien-2-ol, 6,10-dimethyl; and unknown compounds RI1291 and RI1237) was correlated with the startle response (r = 0.620), which is related to an unconscious defensive response. The other group including two VOCs (beta-farnesene and alpha-farnesene) comprised pheromones which increased in KO mice. Next, male mice underwent a social behavior test with female mice in the estrus stage, showing reduced access of KO male mice to female mice. Comparative analysis of urinary VOCs before and after encounters revealed that the six VOCs were not changed by these encounters. However, in WT mice, the two farnesenes increased after the encounters, reaching the level observed in KO mice, which was not altered following the encounter. Taken together, these results indicated that St3gal4 was involved in modulating urinary VOCs. Moreover, VOC clusters discovered by comparison of St3gal4-KO mice with WT mice were correlated with differential emotional behaviors.

Non-Invasive Detection of Anastomotic Leakage Following Esophageal and Pancreatic Surgery by Urinary Analysis

Background: Esophagectomy or pancreaticoduodenectomy is the standard surgical approach for patients with tumors of the esophagus or pancreatic head. Postoperative mortality is strongly correlated with the occurrence of anastomotic leakage (AL). Delay in diagnosis leads to delay in treatment, which ratifies the need for development of novel and accurate non-invasive diagnostic tests for detection of AL. Urinary volatile organic compounds (VOCs) reflect the metabolic status of an individual, which is associated with a systemic immunological response. The aim of this study was to determine the diagnostic accuracy of urinary VOCs to detect AL after esophagectomy or pancreaticoduodenectomy. Methods: In the present study, urinary VOCs of 63 patients after esophagectomy (n = 31) or pancreaticoduodenectomy (n = 32) were analyzed by means of field asymmetric ion mobility spectrometry. AL was defined according to international study groups. Results: AL was observed in 15 patients (24%). Urinary VOCs of patients with AL after pancreaticoduodenectomy could be distinguished from uncomplicated controls, area under the curve 0.85 (95% CI 0.76–0.93), sensitivity 76%, and specificity 77%. However, this was not observed following esophagectomy, area under the curve 0.51 (95% CI 0.37–0.65). Conclusion: In our study population AL following pancreaticoduodenectomy could be discriminated from uncomplicated controls by means of urinary VOC analysis, NTC03203434.

Abstract 5303: FAIMS technology in urinary volatile organic compound analysis to detect colorectal cancer

Abstract Introduction This is an investigation of the capability of FAIMS (Field Asymmetric Ion Mobility Spectrometry) technology as a tool for non-invasive detection of Colorectal Cancer (CRC) through urinary volatile organic compound analysis. It expands on "Detection of Colorectal Cancer (CRC) by Urinary Volatile Organic Compound Analysis" (Ramesh P. Arasaradnam et al, 2014) with an increased sample population and local to Japan, also comparing in-house data of CA19-9 and carcinoembryonic antigen (CEA) markers. Experiment Conducted at Nippon Medical School Chiba Hokusoh Hospital, urine samples were collected and frozen at -80°C from 139 patients at various stages of CRC and 78 healthy control samples. The samples were thawed in batches and placed in ice hours prior to testing. 2 ml of each urine sample was aliquoted into 10 ml vials for processing with the commercial FAIMS device (Lonestar, Owlstone, UK). Each vial was heated in the device to 40°C to create headspace with sufficient VOCs then a carrier gas (clean dry air) delivered the headspace (0.5 L/min) diluted with a make-up flow (2 L/min). The FAIMS device was set to scan at 0 to 100% electric dispersion field in 51 steps and compensation voltage between -6 V and +6 V in 512 steps, producing data matrices for each sample's analysis. Principal Component Analysis (PCA) followed by Partial Least Squares Discriminant Analysis (PLS-DA) of each sample was conducted using SIMCA 13 (Umetrics, Sweden). See Table Conclusions FAIMS technology achieved a high rate of separation between the CRC and healthy control urine samples with 64.7% sensitivity and 82.1% specificity overall. As the CRC stage advances the sensitivity increased from 27.3% to 100%. Results show excellent potential to use FAIMS technology as an early screening tool for CRC, particularly impressive compared to in-house sensitivity data of CA19-9 and CEA markers. Further research into FAIMS screening of other cancer types through VOC biomarker analysis of urine, breath, and feces is recommended. &amp;gt;Detection ResultsCRC STAGEFAIMSOTHER MARKERSCA19-9CEATrue PositiveFalse NegativeSensitivityFalse PositiveTrue NegativeSpecificityNo. of SamplesSensitivitySensitivityI123227.3%146482.1%434.7%18.6%II181260.0%146482.1%3116.1%32.3%III45590.0%146482.1%5219.2%36.5%IV150100%146482.1%1735.3%64.7%ALL904964.7%146482.1%14316.1%33.6% Citation Format: Christopher Psutka, Marina Yamada, Akihisa Matsuda, Kazuya Yamahatsu, Satoshi Matsumoto, Toshihiko Kitayama, Nobuo Nakano, Jyunichi Koyano, Tohru Mikoshiba, Masao Miyashita. FAIMS technology in urinary volatile organic compound analysis to detect colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5303. doi:10.1158/1538-7445.AM2017-5303

Urinary Volatile Organic Compounds as Potential Biomarkers in Idiopathic Membranous Nephropathy

Objective: To detect urinary volatile organic compounds (VOCs) in patients with idiopathic membranous nephropathy (iMN) and normal controls, and to examine whether or not urinary VOCs can act as biomarkers for the diagnosis of iMN independent of renal biopsy. Materials and Methods: Gas chromatography/mass spectrometry (GC/MS) was used to assess the urine collected from 63 iMN patients and 15 normal controls. The statistical methods of principal component analysis and partial least squares discriminant analysis were performed to process the final data in Common Data Format which were converted from GC/MS data. Results: Six VOCs in the urine samples of iMN patients exhibited significant differences from those of normal controls: carbamic acid monoammonium salt, 2-pentanone, 2,4-dimethyl-pentanal, hydrogen azide, thiourea, and 4-heptanone were significantly higher than in controls (p < 0.05). Conclusions: Six urinary VOCs were isolated from patients with iMN using GC/MS. The analysis of urinary VOCs using GC/MS could be developed into a non-invasive method for the detection of iMN.

Volatile organic compounds: A potential biomarker for prediction of hypertension

Background: Human obesity can significantly contribute to hypertension risk, often referred to as the ‘silent killer’, although targeting whom with weight gain becomes clinically hypertensive is unclear. Whilst therapeutic intervention such as bariatric surgery can mitigate both obesity and hypertension, it is not the most suitable solution for all patients. Therefore an early biomarker detection system to assess hypertension in subjects with weight gain could reduce mortality risk. Such a platform could be developed through a urine centred biomarker system identifying disease related signatures based upon volatile organic compounds (VOCs). The focus of this study was to determine whether urinary VOCs could be used as a potential monitoring tool for detection of blood pressure change in obese- hypertensive bariatric patients. Methodology: Pre-surgery urine of 23 obese female patients undergoing bariatric surgery was analysed by Field-Asymmetric Ion Mobility Spectrometer (FAIMS). The data was processed by dividing the cohort into two classifications (high and low) based on individual median values: systolic and diastolic blood pressure, mean arterial pressure (MAP), C-reactive protein (CRP) and heart rate. Support Vector Machine (SVM) classifiers were trained with features selected using the Wilcoxon rank sum test. Performance was assessed using 10-fold cross-validation and the area under the ROC curve (AUC). Results: FAIMS urinary VOC analysis highlighted a significant association with blood pressure markers as determined by systolic (ROC curve AUC: 0.918, P<0.001), MAP (AUC: 0.845 P<0.001), CRP (AUC: 0.932, P<0.001) and heart rate (AUC: 0.945, P<0.001); whilst diastolic did not attain significance (AUC: 0., P=N.S). Additionally the VOCs have predicted change in blood pressure factors 6 months post surgery. Conclusion: This study suggests that urinary VOCs can be used for monitoring change in blood pressure in bariatric patients, additionally this technique could be utilised as a novel-screening tool for prediction of hypertension risk in subjects

LBPS 01-22 VOLATILE ORGANIC COMPOUNDS

Objective: Human obesity can significantly contribute to hypertension risk, often referred to as the “silent killer”, although targeting whom with weight gain becomes clinically hypertensive is unclear. Whilst therapeutic intervention such as bariatric surgery can mitigate both obesity and hypertension, it is not the most suitable solution for all patients. Therefore an early biomarker detection system to assess hypertension in subjects with weight gain could reduce mortality risk. Such a platform could be developed through a urine centred biomarker system identifying disease related signatures based upon volatile organic compounds (VOCs). The focus of this study was to determine whether urinary VOCs could be used as a potential monitoring tool for detection of blood pressure change in obese- hypertensive bariatric patients. Design and Method: Pre-surgery urine of 23 obese female patients undergoing bariatric surgery was analysed by Field-Asymmetric Ion Mobility Spectrometer (FAIMS). The data was processed by dividing the cohort into two classifications (high and low) based on individual median values: systolic and diastolic blood pressure, mean arterial pressure (MAP), C-reactive protein (CRP) and heart rate. Support Vector Machine (SVM) classifiers were trained with features selected using the Wilcoxon rank sum test. Performance was assessed using 10-fold cross-validation and the area under the ROC curve (AUC). Results: FAIMS urinary VOC analysis highlighted a significant association with blood pressure markers as determined by systolic (ROC curve AUC: 0.918, p < 0.001), MAP (AUC: 0.845 p < 0.001), CRP (AUC: 0.932, p < 0.001) and heart rate (AUC: 0.945, p < 0.001); whilst diastolic did not attain significance (AUC: 0., p = N.S). Additionally the VOCs have predicted change in blood pressure factors 6 months post surgery. Conclusions: This study suggests that urinary VOCs can be used for monitoring change in blood pressure in bariatric patients, additionally this technique could be utilised as a novel-screening tool for prediction of hypertension risk in subjects.

PWE-136 The non-invasive detection of non-alcoholic fatty liver disease using urinary volatile organic compound analysis: a pilot study

Introduction Non Alcoholic Fatty Liver Disease (NAFLD) is the commonest cause of chronic liver disease in the western world. Current diagnostic methods, including that of the Fibroscan, have limitations, thus there is a clinical need for more robust, non-invasive screening tools. The gut microbiome is altered in several gastrointestinal and hepatic disorders resulting in altered, unique gut fermentation patterns. These patterns are detectable by analysis of volatile organic compounds (VOCs) in urine, breath and faeces. We aimed to determine if progressive fatty liver disease produced an altered VOC pattern in urine; specifically NAFLD and Non-Alcoholic Steatohepatitis (NASH). Method 34 patients were recruited; 8 NASH cirrhotics (NASH-C); 7 non-cirrhotic NASH; 4 NAFLD and 15 controls. Urine was collected and stored frozen. For assay, the samples were defrosted and aliquoted into vials, which were heated to 40 ± 0.1°C and the headspace analysed by FAIMS (Field Asymmetric Ion Mobility Spectroscopy). A previously used data processing pipeline employing a ‘Random Forrest’ classification algorithm and a 10 fold cross validation method was applied. Results Urinary VOCs could distinguish liver disease patients from controls with a sensitivity of 0.58 (0.33–0.88) but specificity of 0.93 (0.68 – 1.00); Area Under Curve (AUC) 0.73 (0.55 – 0.90). NASH/NASH-C was similarly separated from the NAFLD/control patients with a sensitivity of 0.73 (0.45–0.92), a specificity of 0.79 (0.54–0.94) and AUC of 0.79 (0.64–0.95), respectively. Conclusion This pilot study offers the potential for early non-invasive tracking of liver disease using urinary VOC bio-odorant fingerprints to distinguish patients with a disease within the spectrum of fatty liver disease from healthy controls, but also to distinguish subsets of the spectrum from each other, such as NASH from NAFLD. This may develop into a viable alternative surveillance or diagnostic tool in patients unable or unwilling to undergo liver biopsy. Disclosure of interest None Declared.

Non-invasive distinction of non-alcoholic fatty liver disease using urinary volatile organic compound analysis: early results.

Non-Alcoholic Fatty Liver Disease (NAFLD) is the commonest cause of chronic liver disease in the western world. Current diagnostic methods including Fibroscan have limitations, thus there is a need for more robust non-invasive screening methods. The gut microbiome is altered in several gastrointestinal and hepatic disorders resulting in altered, unique gut fermentation patterns, detectable by analysis of volatile organic compounds (VOCs) in urine, breath and faeces. We performed a proof of principle pilot study to determine if progressive fatty liver disease produced an altered urinary VOC pattern; specifically NAFLD and Non-Alcoholic Steatohepatitis (NASH). 34 patients were recruited: 8 NASH cirrhotics (NASH-C); 7 non-cirrhotic NASH; 4 NAFLD and 15 controls. Urine was collected and stored frozen. For assay, the samples were defrosted and aliquoted into vials, which were heated to 40±0.1°C and the headspace analyzed by FAIMS (Field Asymmetric Ion Mobility Spectroscopy). A previously used data processing pipeline employing a Random Forrest classification algorithm and using a 10 fold cross validation method was applied. Urinary VOC results demonstrated sensitivity of 0.58 (0.33 - 0.88), but specificity of 0.93 (0.68 - 1.00) and an Area Under Curve (AUC) 0.73 (0.55 - 0.90) to distinguish between liver disease and controls. However, NASH/NASH-C was separated from the NAFLD/controls with a sensitivity of 0.73 (0.45 - 0.92), specificity of 0.79 (0.54 - 0.94) and AUC of 0.79 (0.64 - 0.95), respectively. This pilot study suggests that urinary VOCs detection may offer the potential for early non-invasive characterisation of liver disease using 'smell prints' to distinguish between NASH and NAFLD.

Differentiating coeliac disease from irritable bowel syndrome by urinary volatile organic compound analysis--a pilot study.

Coeliac disease (CD), a T-cell-mediated gluten sensitive enteropathy, affects ∼1% of the UK population and can present with wide ranging clinical features, often being mistaken for Irritable Bowel Syndrome (IBS). Heightened clinical awareness and serological screening identifies those with potential coeliac disease; the diagnosis is confirmed with duodenal biopsies, and symptom improvement with a gluten-free diet. Limitations to diagnosis are false negative serology and reluctance to undergo biopsy. The gut microbiome is altered in several gastrointestinal disorders, causing altered gut fermentation patterns recognisable by volatile organic compounds (VOC) analysis in urine, breath and faeces. We aimed to determine if CD alters the urinary VOC pattern, distinguishing it from IBS. 47 patients were recruited, 27 with established CD, on gluten free diets, and 20 with diarrhoea-predominant IBS (D-IBS). Collected urine was stored frozen in 10 ml aliquots. For assay, the specimens were heated to 40±0.1°C and the headspace analysed by Field Asymmetric Ion Mobility Spectrometry (FAIMS). Machine learning algorithms were used for statistical evaluation. Samples were also analysed using Gas chromatography and mass spectroscopy (GC-MS). Sparse logistic regression showed that FAIMS distinguishes VOCs in CD vs D-IBS with ROC curve AUC of 0.91 (0.83–0.99), sensitivity and specificity of 85% respectively. GCMS showed a unique peak at 4′67 found only in CD, not D-IBS, which correlated with the compound 1,3,5,7 cyclooctatetraene. This study suggests that FAIMS offers a novel, non-invasive approach to identify those with possible CD, and distinguishes from D-IBS. It offers the potential for monitoring compliance with a gluten-free diet at home. The presence of cyclooctatetraene in CD specimens will need further validation.

Detection of colorectal cancer (CRC) by urinary volatile organic compound analysis.

Colorectal cancer (CRC) is a leading cause of cancer related death in Europe and the USA. There is no universally accepted effective non-invasive screening test for CRC. Guaiac based faecal occult blood (gFOB) testing has largely been superseded by Faecal Immunochemical testing (FIT), but sensitivity still remains poor. The uptake of population based FOBt testing in the UK is also low at around 50%. The detection of volatile organic compounds (VOCs) signature(s) for many cancer subtypes is receiving increasing interest using a variety of gas phase analytical instruments. One such example is FAIMS (Field Asymmetric Ion Mobility Spectrometer). FAIMS is able to identify Inflammatory Bowel disease (IBD) patients by analysing shifts in VOCs patterns in both urine and faeces. This study extends this concept to determine whether CRC patients can be identified through non-invasive analysis of urine, using FAIMS. 133 patients were recruited; 83 CRC patients and 50 healthy controls. Urine was collected at the time of CRC diagnosis and headspace analysis undertaken using a FAIMS instrument (Owlstone, Lonestar, UK). Data was processed using Fisher Discriminant Analysis (FDA) after feature extraction from the raw data. FAIMS analyses demonstrated that the VOC profiles of CRC patients were tightly clustered and could be distinguished from healthy controls. Sensitivity and specificity for CRC detection with FAIMS were 88% and 60% respectively. This study suggests that VOC signatures emanating from urine can be detected in patients with CRC using ion mobility spectroscopy technology (FAIMS) with potential as a novel screening tool.