Methane Gas in Breath Test is Associated with Non-Alcoholic Fatty Liver Disease.

Although the association between Body Mass Index (BMI) level and metabolic diseases as well as the association between the breath test results and BMI level have been studied, their relationship between breath hydrogen/methane level and metabolic diseases need to be further clarified. This study aimed to investigate how the composition of exhaled breath gases relates to metabolic disorders and their key risk factors. An elevated BMI level significantly increases the risk of developing metabolic disease; it was included in this study to find their association. Diabetes mellitus, dyslipidemia, hypertension, and non-alcoholic fatty liver disease (NAFLD) are metabolic diseases included in this study. An analysis was performed on the medical records including the lactulose breath test (LBT) data of patients who visited the Ajou University Medical Center, Suwon, Republic of Korea, between January 2016 and December 2021. Subjects were grouped according to four different criteria of the LBT hydrogen and methane level: 1) Normal (N) (Hydrogen < 20 ppm and Methane < 3 ppm); 2) Hydrogen only (H+) (Hydrogen ≥ 20 ppm and Methane < 3 ppm); 3) Methane positive (M+) (Hydrogen < 20 ppm and Methane ≥ 3 ppm); and 4) Methane and hydrogen positive (M+/H+) (Hydrogen ≥ 20 ppm and Methane ≥ 3 ppm). Of 441 subjects, 325 (72.1%) had positive results for methane only (M+). BMI and prevalence of NAFLD were higher in subjects with M+ than in subjects with hydrogen and methane positivity (H+/M+). According to multivariate analysis, the odds ratio (OR) of M+ was 2.002 (with 95% CI: 1.244-3.221, P = 0.004) for NAFLD. Our results demonstrate that breath methane positivity is related to NAFLD and suggest that increased methane gas in breath tests has the potential to be an easily measurable biomarker for the diagnosis of NAFLD. .

Detection and clinical application of red blood cell survival. / çº¢ç»†èƒžå¯¿å‘½çš„æ£€æµ‹åŠå ¶ä¸´åºŠåº”ç”¨.

There are 2 techniques for detecting red blood cell survival (RBCS) detection techniques: red blood cell labeling test and carbon monoxide (CO) breath test. The former has disadvantages such as long measurement times and complicated procedures, while the latter is simple, convenient, moderately priced, and capable of dynamically monitoring changes in RBCS before and after treatment. Currently, the CO breath test is gradually being implemented in clinical practice. RBCS is not only applied to hematologic diseases such as multiple myeloma, myelodysplastic syndromes, lymphoma, and thalassemia, but also to non-hematologic diseases like type 2 diabetes and chronic kidney disease. It can assist in diagnosis, guide treatment, evaluate drug treatment efficacy, and predict disease progression.

Diagnosing sucrase-isomaltase deficiency: a comparison of a 13C-sucrose breath test and a duodenal enzyme assay.

BACKGROUND: Reduced activity of the sucrase-isomaltase (SI) enzyme can cause gastrointestinal symptoms. Biochemical measurement of SI activity in small intestinal biopsies is presently considered the gold standard for the diagnosis of SI deficiency, but this invasive test is not suitable as a routine diagnostic tool. AIM: To evaluate a 13C-sucrose-breath test (13CSBT) as a diagnostic tool for SI deficiency in an adult population. METHODS: 13CSBT results were compared to sucrase activity measured in duodenal biopsies. RESULTS: Forty patients with gastrointestinal symptoms were included in the study, 4 of whom had celiac disease and the rest (n = 36) had normal histological findings. Nine patients (22.5%) had low sucrase activity measured using duodenal biopsies. No correlation was observed between enzymatic sucrase activity and the 13CSBT results. The 13CSBT-curves for the celiac patients versus patients with normal duodenal histology demonstrated that the patients with celiac disease were within the lower range of the distribution. CONCLUSION: We observed a mismatch between the 13CSBT results and the biochemically measured sucrase activity, suggesting that SI activity is not uniformly distributed throughout the small intestines. This methodological discrepancy should be acknowledged when diagnosing SI deficiency.

Electronic nose based analysis of exhaled volatile organic compounds spectrum reveals asthmatic shifts and consistency in controls post-exercise and spirometry.

Analyzing exhaled volatile organic compounds (VOCs) with an electronic nose (e-nose) is emerging in medical diagnostics as a non-invasive, quick, and sensitive method for disease detection and monitoring. This study investigates if activities like spirometry or physical exercise affect exhaled VOCs measurements in asthmatics and healthy individuals, a crucial step for e-nose technology's validation for clinical use. The study analyzed exhaled VOCs using an e-nose in 27 healthy individuals and 27 patients with stable asthma, before and after performing spirometry and climbing five flights of stairs. Breath samples were collected using a validated technique and analyzed with a Cyranose 320 e-nose. In healthy controls, the exhaled VOCs spectrum remained unchanged after both lung function test and exercise. In asthmatics, principal component analysis and subsequent discriminant analysis revealed significant differences post-spirometry (vs. baseline 66.7% cross validated accuracy [CVA],p< 0.05) and exercise (vs. baseline 70.4% CVA,p< 0.05). E-nose measurements in healthy individuals are consistent, unaffected by spirometry or physical exercise. However, in asthma patients, significant changes in exhaled VOCs were detected post-activities, indicating airway responses likely due to constriction or inflammation, underscoring the e-nose's potential for respiratory condition diagnosis and monitoring.

Helicobacter pylori in gastrointestinal manifestation of systemic sclerosis.

Aim: To study the prevalence of Helicobacter pylori in systemic sclerosis patients and its gastrointestinal manifestations in comparison with Helicobacter pylori-negative systemic sclerosis patients. Systemic sclerosis gastrointestinal outcome post Helicobacter pylori eradication was evaluated. Method: In total, 70 systemic sclerosis patients and 70 age-, gender- and race-matched healthy controls had their urea breath test done. Gastrointestinal manifestations in systemic sclerosis were assessed using University of California at Los Angeles 2.0 and Leeds Dyspepsia Questionnaire questionnaires. Systemic sclerosis patients with confirmed Helicobacter pylori infection were given standard Helicobacter pylori eradication therapy. Urea breath test was repeated 6 weeks posteradication therapy with their gastrointestinal symptoms reassessed. Results: The prevalence of Helicobacter pylori was low in both systemic sclerosis patients (10%) and healthy controls (2.9%). There was no significant difference in gastrointestinal symptoms between Helicobacter pylori-positive and Helicobacter pylori-negative systemic sclerosis patients. However, the Helicobacter pylori-positive patients reported higher median severity scores for the gastrointestinal symptoms of reflux (0.5 vs 0.35), abdominal distension (1.5 vs 0.75) and social functioning impairment score (0.5 vs 0.16) using the University of California at Los Angeles 2.0 score. The Helicobacter pylori-positive patients also indicated increased upper abdominal pain (3.0 vs 0.0), regurgitation (2.0 vs 0.0) and burping (3.0 vs 0.0), observed from the Leeds Dyspepsia Questionnaire scores. Gastrointestinal outcomes post-Helicobacter pylori eradication showed either an improvement or complete resolution of symptoms. Conclusion: Gastrointestinal symptoms in systemic sclerosis patients are unlikely to be caused by Helicobacter pylori in the recent years in our cohort of patients. No significant difference in gastrointestinal symptoms was seen between Helicobacter pylori-positive and Helicobacter pylori-negative systemic sclerosis patients. Helicobacter pylori can be readily tested by urea breath test to look for present infection.

Fecal Coprococcus, hidden behind abdominal symptoms in patients with small intestinal bacterial overgrowth.

BACKGROUND: Small intestinal bacterial overgrowth (SIBO) is the presence of an abnormally excessive amount of bacterial colonization in the small bowel. Hydrogen and methane breath test has been widely applied as a non-invasive method for SIBO. However, the positive breath test representative of bacterial overgrowth could also be detected in asymptomatic individuals. METHODS: To explore the relationship between clinical symptoms and gut dysbiosis, and find potential fecal biomarkers for SIBO, we compared the microbial profiles between SIBO subjects with positive breath test but without abdominal symptoms (PBT) and healthy controls (HC) using 16S rRNA amplicon sequencing. RESULTS: Fecal samples were collected from 63 SIBO who complained of diarrhea, distension, constipation, or abdominal pain, 36 PBT, and 55 HC. For alpha diversity, the Shannon index of community diversity on the genus level showed a tendency for a slight increase in SIBO, while the Shannon index on the predicted function was significantly decreased in SIBO. On the genus level, significantly decreased Bacteroides, increased Coprococcus_2, and unique Butyrivibrio were observed in SIBO. There was a significant positive correlation between saccharolytic Coprococcus_2 and the severity of abdominal symptoms. Differently, the unique Veillonella in the PBT group was related to amino acid fermentation. Interestingly, the co-occurrence network density of PBT was larger than SIBO, which indicates a complicated interaction of genera. Coprococcus_2 showed one of the largest betweenness centrality in both SIBO and PBT microbiota networks. Pathway analysis based on the Kyoto Encyclopedia of Genes and Genome (KEGG) database reflected that one carbon pool by folate and multiple amino acid metabolism were significantly down in SIBO. CONCLUSIONS: This study provides valuable insights into the fecal microbiota composition and predicted metabolic functional changes in patients with SIBO. Butyrivibrio and Coprococcus_2, both renowned for their role in carbohydrate fermenters and gas production, contributed significantly to the symptoms of the patients. Coprococcus's abundance hints at its use as a SIBO marker. Asymptomatic PBT individuals show a different microbiome, rich in Veillonella. PBT's complex microbial interactions might stabilize the intestinal ecosystem, but further study is needed due to the core microbiota similarities with SIBO. Predicted folate and amino acid metabolism reductions in SIBO merit additional validation.

Evaluation of urea breath test as a diagnostic tool for Helicobacter pylori infection in adult dyspeptic patients.

In this editorial, we discuss the article in the World Journal of Gastroenterology. The article conducts a meta-analysis of the diagnostic accuracy of the urea breath test (UBT), a non-invasive method for detecting Helicobacter pylori (H. pylori) infection in humans. It is based on radionuclide-labeled urea. Various methods, both invasive and non-invasive, are available for diagnosing H. pylori infection, including endoscopy with biopsy, serology for immunoglobulin titers, stool antigen analysis, and UBT. Several guidelines recommend UBTs as the primary choice for diagnosing H. pylori infection and for reexamining after eradication therapy. It is used to be the first choice non-invasive test due to their high accuracy, specificity, rapid results, and simplicity. Moreover, its performance remains unaffected by the distribution of H. pylori in the stomach, allowing a high flow of patients to be tested. Despite its widespread use, the performance characteristics of UBT have been inconsistently described and remain incompletely defined. There are two UBTs available with Food and Drug Administration approval: The 13C and 14C tests. Both tests are affordable and can provide real-time results. Physicians may prefer the 13C test because it is non-radioactive, compared to 14C which uses a radioactive isotope, especially in young children and pregnant women. Although there was heterogeneity among the studies regarding the diagnostic accuracy of both UBTs, 13C-UBT consistently outperforms the 14C-UBT. This makes the 13C-UBT the preferred diagnostic approach. Furthermore, the provided findings of the meta-analysis emphasize the significance of precise considerations when choosing urea dosage, assessment timing, and measurement techniques for both the 13C-UBT and 14C-UBT, to enhance diagnostic precision.

MASLD can cause halitosis by small intestinal bacterial overgrowth.

OBJECTIVES: Patients with metabolic dysfunction-associated steatotic liver disease (MASLD) exhibit varying degrees of halitosis. The author speculated that small intestinal bacterial overgrowth (SIBO) might lead to MASLD and subsequent extra-oral halitosis and aimed to test this hypothesis. METHODS: This retrospective cross-sectional study reviewed 885 extra-oral halitosis patients. Halitosis and exhaled dimethyl sulfide (DMS) were measured by organoleptic score (OLS) (0-5) and OralChroma, respectively. SIBO and MASLD were diagnosed by hydrogen breath test and Fibroscan combined with cardiometabolic criteria. RESULTS: In this study, 133/885 (15.05%) of the halitosis patients otherwise healthy had MASLD, while 87/133 (65.41%) of the MASLD patients were SIBO-positive. No significant differences were observed in physical parameters such as age, serum biochemical parameters such as lipids, or Fibroscan parameters between the SIBO-positive and SIBO-negative patients. However, the OLS was 4 (interquartile range: 3-4) and exhaled DMS level was 56 (43-75) parts per billion (ppb) in the SIBO-positive patients, significantly greater than 2 (2-3) and 43 (25-51) ppb in the SIBO-negative patients (both p < 0.001). Exhaled hydrogen levels positively correlated with the OLS and exhaled DMS levels (r = 0.774, r = 0.740, both p < 0.001). CONCLUSION: MASLD can cause halitosis by SIBO.

Features of exocrine pancreatic insufficiency in patients with non-alcoholic fatty liver disease in combination with type 2 diabetes and COVID-19.

OBJECTIVE: Aim: The aim of the research was to study the features of pancreatic exocrine insufficiency (EPI) in patients with nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (DM) at COVID-19. PATIENTS AND METHODS: Materials and Methods: 72 patients with NAFLD and COVID-19 were examined. The patients have been divided into two groups: group 1 included 42 patients with NAFLD and insulin resistance (IR); group 2 consisted of 30 patients with NAFLD in the combination with type 2 DM. EPI was detected by 13С-mixed triglyceride breath test (13С-MTBT) in all the patients. RESULTS: Results: The result of 13С-MTBT indicates EPI in the examined subjects of the 2 group. A significant decrease in the maximum concentration of 13СО2 between 150 and 210 min was also diagnosed in group 1 patients. research (up to 8.2 ± 0.9% - p < 0.05), however, the total concentration of 13СО2 at the end of 360 min. the study reached only 27.7 ± 1.1% (p < 0.05). CONCLUSION: Conclusions: Based on the results of laboratory-instrumental methods of research, patients with NAFLD and type 2 diabetes with COVID-19 were diagnosed with severe EPI. The results of 13С-MTBT in NAFLD and IR with COVID-19 indicate a decrease in the functional reserves of the pancreas and the formation of its EPI.

The current infection with Helicobacter pylori and association with upper gastrointestinal lesions and risk of upper gastrointestinal cancer: Insights from multicenter population-based cohort study.

The relationship between Helicobacter pylori (H. pylori) infection and upper gastrointestinal (UGI) cancers is complex. This multicenter, population-based cohort study conducted in seven areas in China aimed to assess the correlation between current H. pylori infection and the severity of UGI lesions, as well as its association with the risk of gastric cancer (GC) and esophageal cancer (EC). From 2015 to 2017, 27,085 participants (aged 40-69) completed a standardized questionnaire, and underwent a 13C-urea breath test. Then a subset underwent UGI endoscopy to assess the UGI lesion detection rates. All individuals were followed up until December 2021 to calculate the hazard ratios (HRs) for UGI cancers. H. pylori infection prevalence was 45.9%, and among endoscopy participants, 22.2% had gastric lesions, 19.2% had esophageal lesions. Higher detection rates of gastric lesions were noted in the H. pylori-positive population across all lesion severity levels. Over a median follow-up of 6.3 years, 104 EC and 179 GC cases were observed, including 103 non-cardia gastric cancer (NCGC) cases and 76 cardia gastric cancer (CGC) cases. H. pylori-infected individuals exhibited a 1.78-fold increased risk of GC (HR 1.78, 95% confidence interval [CI] 1.32-2.40) but no significant increase in EC risk (HR 1.07, 95% CI 0.73-1.57). Notably, there was a higher risk for both NCGC and CGC in H. pylori-infected individuals. This population-based cohort study provides valuable evidence supporting the association between current H. pylori infection and the risk of both NCGC and CGC. These findings contribute to the empirical basis for risk stratification and recommendations for UGI cancer screening.

Lactase for infantile colic: A systematic review of randomized clinical trials.

Infantile colic is excessive crying for no apparent reason in an otherwise healthy infant. Although its physiopathology is not completely understood, therapies usually target gastrointestinal symptoms. This systematic review of randomized controlled trials (RCTs) analyzes the efficacy of lactase supplementation in infantile colic. PubMed, Embase, and Cochrane were searched for RCTs evaluating lactase supplementation in infants up to 6 months old with infantile colic. Out of six RCTs including 394 patients, three reported a significantly shorter crying time in the lactase group than in the placebo group, while the other three found no significant difference between groups. Of the two studies that performed the hydrogen breath test, only one reported a significant reduction in exhaled hydrogen levels.  The pharmacological approach to infantile colic remains debatable, and new studies with standardized diagnostic criteria and outcomes are required to guide lactase supplementation in clinical practice.

Critical appraisal of the SIBO hypothesis and breath testing: A clinical practice update endorsed by the European society of neurogastroenterology and motility (ESNM) and the American neurogastroenterology and motility society (ANMS).

BACKGROUND: There is compelling evidence that microbe-host interactions in the intestinal tract underlie many human disorders, including disorders of gut-brain interactions (previously termed functional bowel disorders), such as irritable bowel syndrome (IBS). Small intestinal bacterial overgrowth (SIBO) has been recognized for over a century in patients with predisposing conditions causing intestinal stasis, such as surgical alteration of the small bowel or chronic diseases, including scleroderma and is associated with diarrhea and signs of malabsorption. Over 20 years ago, it was hypothesized that increased numbers of small intestine bacteria might also account for symptoms in the absence of malabsorption in IBS and related disorders. This SIBO-IBS hypothesis stimulated significant research and helped focus the profession's attention on the importance of microbe-host interactions as a potential pathophysiological mechanism in IBS. PURPOSE: However, after two decades, this hypothesis remains unproven. Moreover, it has led to serious unintended consequences, namely the widespread use of unreliable and unvalidated breath tests as a diagnostic test for SIBO and a resultant injudicious use of antibiotics. In this review, we examine why the SIBO hypothesis remains unproven and, given the unintended consequences, discuss why it is time to reject this hypothesis and its reliance on breath testing. We also examine recent IBS studies of bacterial communities in the GI tract, their composition and functions, and their interactions with the host. While these studies provide important insights to guide future research, they highlight the need for further mechanistic studies of microbe-host interactions in IBS patients before we can understand their possible role in diagnosis and treatment of patient with IBS and related disorders.

Cardio-Hepatic Interaction in Cardiac Amyloidosis.

Background: Congestion is associated with poor prognosis in cardiac amyloidosis (CA). The cardio-hepatic interaction and the prognostic impact of secondary liver affection by cardiac congestion in CA are poorly understood and require further characterisation. Methods: Participants of the amyloidosis cohort study AmyKoS at the Interdisciplinary Amyloidosis Centre of Northern Bavaria with proven transthyretin (ATTR-CA) and light chain CA (AL-CA) underwent serial work-up including laboratory tests, echocardiography, and in-depth hepatic assessment by vibration-controlled transient elastography (VCTE) and 13C-methacetin breath test. Results: In total, 74 patients with AL-CA (n = 17), ATTR-CA (n = 26) and the controls (n = 31) were analysed. ATTR-CA patients showed decreased microsomal liver function expressed by maximal percentage of dose rate (PDRpeak) related to hepatic congestion. Reduced PDRpeak in AL-CA could result from altered pharmacokinetics due to changed hepatic blood flow. Liver stiffness as a combined surrogate of chronic liver damage and congestion was identified as a predictor of all-cause mortality. Statistical modelling of the cardio-hepatic interaction revealed septum thickness, NT-proBNP and PDRpeak as predictors of liver stiffness in both CA subtypes; dilatation of liver veins and the fibrosis score FIB-4 were only significant for ATTR-CA. Conclusions: Non-invasive methods allow us to characterise CA-associated hepatic pathophysiology. Liver stiffness might be promising for risk stratification in CA.

Fructose malabsorption and fructan malabsorption are associated in patients with irritable bowel syndrome.

BACKGROUND: Food malabsorption and intolerance is implicated in gastrointestinal symptoms among patients with irritable bowel syndrome (IBS). Key triggers include fructose and fructan. Prior studies examined fructose and fructan malabsorption separately in IBS patients. None have concurrently assessed both within the same patient group. We aimed to investigate the association between fructose and fructan malabsorption in the same patients with IBS using hydrogen breath testing (HBT). METHODS: We retrospectively identified patients with IBS who underwent fructose and fructan HBTs and abstracted their results from the electronic medical record. Fructose and fructan HBTs were performed by administering a 25 g fructose solution or 10 g fructan solution, followed by breath hydrogen readings every 30 min for 3 h. Patients were positive for fructose or fructan malabsorption if breath hydrogen levels exceeded 20 ppm. RESULTS: Of 186 IBS patients, 71 (38.2%) were positive for fructose malabsorption and 91 (48.9%) were positive for fructan malabsorption. Of these patients, 42 (22.6%) were positive for fructose malabsorption and fructan malabsorption. Positive fructose HBT readings were significantly associated with positive fructan HBT readings (p = 0.0283). Patients positive for fructose malabsorption or fructan malabsorption had 1.951 times higher odds of testing positive for the other carbohydrate. CONCLUSIONS: Our results reveal a clinically significant association between fructose malabsorption and fructan malabsorption in patients with IBS. Fructan malabsorption should be assessed in patients with fructose malabsorption, and vice versa. Further studies are required to identify the mechanisms underlying our findings.

Evaluation of probiotics in the treatment of hypothyroidism in early pregnancy combined with small intestinal bacterial overgrowth.

The aim of this study was to investigate the association between hypothyroidism in early pregnancy and small intestinal bacterial overgrowth (SIBO) and the effect of probiotics. Patients with hypothyroidism in early pregnancy and normal pregnant women during the same period were included in the methane-hydrogen breath test to compare the incidence of SIBO, smoothed curve fit, and differences in clinical symptoms. For those who combined with SIBO, the rate of clinical symptom conversion, thyroid hormones, and changes in associated inflammatory indexes were compared after 21 days of treatment with probiotics on top of conventional levothyroxine sodium tablets. The results are as follows: (1) The incidence of combined SIBO in patients with hypothyroidism in pregnancy was 56.0%, significantly higher than the 28.0% of normal pregnant women during the same period. (2) The highest value of hydrogen plus methane gas in 90 min in pregnancy hypothyroid patients showed a significant negative correlation with FT4 (p < .001, SD = 0.169). (3) Abdominal distension symptoms were significantly increased in both groups after combined SIBO (p = .036, p = .025), and the conversion rate after treatment was 69.2% and 75.0%, respectively. (4) In hypothyroidism, pregnancy combined with SIBO, TSH, and CRP was higher before treatment (p = .001, p = .012) and decreased significantly after treatment (p = .001, p = .008). Hypothyroidism in early pregnancy is associated with SIBO, and probiotic treatment is significantly effective.

Ammonia measurement in human breath of subjects with Helicobacter pylori using photoacoustic spectroscopy.

Helicobacter pylori (H. pylori) is a type of bacteria that infects the stomach. The detection of H. pylori is an essential part of current clinical practices because this disease can cause peptic ulcers, chronic inflammation of the stomach lining but also stomach cancer. Helicobacter pylori has a naturally occurring enzyme that hydrolyzes urea into ammonium carbonate called urease. Many methods exist for the detection of H. pylori infection, but an innovative approach is to detect the ammonia in the breath (ABT, Ammonia Breath Test). In this research study, using photoacoustic spectroscopy method, the ammonia concentration in the breathing zone of people with H. pylori were measured and were compared with ammonia concentration from the respiration of healthy people. From the ABT determinations of this study, the ammonia was established to be increased with 498 ppb at people with H. pylori when we compare with ABT of healthy people.

Glucose breath test for the detection of small intestine bacterial overgrowth: Impact of diet prior to the test.

BACKGROUND: Glucose breath test (GBT) is used for the diagnosis of small intestine bacterial overgrowth. A restrictive diet without fibers and/or fermentable food is recommended on the day before the test. The aim of our retrospective study was to evaluate the impact of two different restrictive diets on the results of GBT. METHODS: A change of the pretest restrictive diet was applied in our lab on September 1, 2020. The recommended diet was a fiber-free diet before this date, and a fiber-free diet plus restriction of all fermentable food afterward. We thus compared the results of GBT performed before (group A) and after (group B) this pretest diet modification. Demographics, reasons to perform GBT, digestive symptoms, and hydrogen and methane baseline values and variations after glucose ingestion were compared between the two groups. KEY RESULTS: 269 patients underwent GBT in group A, and 316 patients in group B. The two groups were comparable in terms of demographics. Methane and hydrogen baseline values were significantly higher in group A (respectively 14 [18] vs. 8 [14] ppm, p < 0.01 and 11 [14] vs. 6 [8] ppm, p < 0.01). The percentage of positive tests was higher in group A for methane (43% vs. 28%, p < 0.05), and for hydrogen (18% vs. 12%, p = 0.03). CONCLUSION & INFERENCES: This retrospective study suggests the importance of the restrictive diet prior to GBT. A strict limitation of fibers and fermentable food decreased hydrogen and methane baseline values, and the prevalence of positive GBT. Thus a strict restrictive diet should be recommended on the day before the test, in order to limit the impact of food on hydrogen and methane breath levels, and possibly improve the diagnosis quality of GBT.

The 13C glucose breath test accurately identifies insulin resistance in people with type 1 diabetes.

OBJECTIVE: This study investigated whether the delta-over-baseline of exhaled 13CO2 (Δ13CO2), generated from a 13C glucose breath test (13C-GBT), measured insulin resistance (IR) in people with type 1 diabetes, using the hyperinsulinemic-euglycemic clamp (HEC) as reference method. Secondary objective was to compare the 13C-GBT with the estimated glucose disposal rate (eGDR). METHODS: A 40 mU/m2/min HEC and two separate 13C-GBTs (euglycemic with insulin bolus and hyperglycemic without bolus) were consecutively performed in 44 adults with type 1 diabetes with varying body compositions. eGDR was calculated based on HbA1c, presence of hypertension and waist circumference. RESULTS: Mean M-value was 5.9 ± 3.1 mg/kg/min, mean euglycemic Δ13CO2 was 6.4 ± 2.1 δ‰, while median eGDR was 5.9 [4.3 - 9.8] mg/kg/min. The hyperglycemic Δ13CO2 did not correlate with the M-value, while the euglycemic Δ13CO2 and the M-value correlated strongly (r = 0.74, p < 0.001). Correlation between M-value and eGDR was more moderate (Spearman's rho = 0.63, p < 0.001). Linear regression showed an association between Δ13CO2 and M-value, adjusted for age, sex and HbA1c (adjusted R² = 0.52, B = 1.16, 95% CI 0.80 - 1.52, p < 0.001). The AUROC for Δ13CO2 to identify subjects with IR (M-value < 4.9 mg/kg/min) was 0.81 (95% CI 0.68 - 0.94, p < 0.001). The optimal cut-off for Δ13CO2 to identify subjects with IR was ≤ 5.8 δ‰. CONCLUSIONS: Under euglycemic conditions, the 13C-GBT accurately identified individuals with type 1 diabetes and concurrent IR, suggesting its potential as a valuable non-invasive index.

Urea breath test for Helicobacter pylori infection in adult dyspeptic patients: A meta-analysis of diagnostic test accuracy.

BACKGROUND: Helicobacter pylori (H. pylori) infection has been well-established as a significant risk factor for several gastrointestinal disorders. The urea breath test (UBT) has emerged as a leading non-invasive method for detecting H. pylori. Despite numerous studies confirming its substantial accuracy, the reliability of UBT results is often compromised by inherent limitations. These findings underscore the need for a rigorous statistical synthesis to clarify and reconcile the diagnostic accuracy of the UBT for the diagnosis of H. pylori infection. AIM: To determine and compare the diagnostic accuracy of 13C-UBT and 14C-UBT for H. pylori infection in adult patients with dyspepsia. METHODS: We conducted an independent search of the PubMed/MEDLINE, EMBASE, and Cochrane Central databases until April 2022. Our search included diagnostic accuracy studies that evaluated at least one of the index tests (13C-UBT or 14C-UBT) against a reference standard. We used the QUADAS-2 tool to assess the methodological quality of the studies. We utilized the bivariate random-effects model to calculate sensitivity, specificity, positive and negative test likelihood ratios (LR+ and LR-), as well as the diagnostic odds ratio (DOR), and their 95% confidence intervals. We conducted subgroup analyses based on urea dosing, time after urea administration, and assessment technique. To investigate a possible threshold effect, we conducted Spearman correlation analysis, and we generated summary receiver operating characteristic (SROC) curves to assess heterogeneity. Finally, we visually inspected a funnel plot and used Egger's test to evaluate publication bias. RESULTS: The titles and abstracts of 4621 studies were screened; 79 articles were retrieved and selected for full-text reading. Finally, 60 studies were included in the diagnostic test accuracy meta-analysis. Our analysis demonstrates superior diagnostic accuracy of 13C-UBT over 14C-UBT, indicated by higher sensitivity (96.60% vs 96.15%), specificity (96.93% vs 89.84%), likelihood ratios (LR+ 22.00 vs 10.10; LR- 0.05 vs 0.06), and area under the curve (AUC; 0.979 vs 0.968). Notably, 13C-UBT's DOR (586.47) significantly outperforms 14C-UBT (DOR 226.50), making it the preferred diagnostic tool for dyspeptic individuals with H. pylori infection. Correlation analysis revealed no threshold effect (13C-UBT: r = 0.48; 14C-UBT: r = -0.01), and SROC curves showed consistent accuracy. Both 13C-UBT and 14C-UBT showed high AUC values (13C-UBT 0.979; 14C-UBT 0.968) near 1.00, reinforcing their excellent accuracy and endorsing both as reliable diagnostic tools in clinical practice. CONCLUSION: In summary, our study has demonstrated that 13C-UBT has been found to outperform the 14C-UBT, making it the preferred diagnostic approach. Additionally, our results emphasize the significance of carefully considering urea dosage, assessment timing, and measurement techniques for both tests to enhance diagnostic precision. Nevertheless, it is crucial for researchers and clinicians to evaluate the strengths and limitations of our findings before implementing them in practice.

Nanowire Array Breath Acetone Sensor for Diabetes Monitoring.

Diabetic ketoacidosis (DKA) is a life-threatening acute complication of diabetes characterized by the accumulation of ketone bodies in the blood. Breath acetone, a ketone, directly correlates with blood ketones. Therefore, monitoring breath acetone can significantly enhance the safety and efficacy of diabetes care. In this work, the design and fabrication of an InP/Pt/chitosan nanowire array-based chemiresistive acetone sensor is reported. By incorporation of chitosan as a surface-functional layer and a Pt Schottky contact for efficient charge transfer processes and photovoltaic effect, self-powered, highly selective acetone sensing is achieved. The sensor has exhibited an ultra-wide acetone detection range from sub-ppb to >100 000 ppm level at room temperature, covering those in the exhaled breath from healthy individuals (300-800 ppb) to people at high risk of DKA (>75 ppm). The nanowire sensor has also been successfully integrated into a handheld breath testing prototype, the Ketowhistle, which can successfully detect different ranges of acetone concentrations in simulated breath samples. The Ketowhistle demonstrates the immediate potential for non-invasive ketone monitoring for people living with diabetes, in particular for DKA prevention.