Breath Tests Used in the Context of Bariatric Surgery.

This review article focuses on the use of breath tests in the field of bariatrics and obesitology. The first part of the review is an introduction to breath test problematics with a focus on their use in bariatrics. The second part provides a brief history of breath testing. Part three describes how breath tests are used for monitoring certain processes in various organs and various substances in exhaled air and how the results are analyzed and evaluated. The last part covers studies that described the use of breath tests for monitoring patients that underwent bariatric treatments. Although the number of relevant studies is small, this review could promote the future use of breath testing in the context of bariatric treatments.

Faecal immunochemical tests for haemoglobin: Analytical challenges and potential solutions.

Quantitative faecal immunochemical tests for haemoglobin (FIT) are being used increasingly around the world in colorectal cancer screening programmes, and in patients presenting with lower bowel symptoms to determine who should proceed to further bowel visualisation investigations, usually colonoscopy. The clinical utility of FIT is well reported. There are a number of analytical challenges including pre-analytical variation, difficulty setting up external quality assessment schemes, access to third party internal quality control material and a lack of standardisation or harmonisation of FIT methods. Here we report the work of the International Federation of Clinical Chemistry FIT Working Group. We provide an overview of the main pre-analytical variables; discuss different approaches to external quality assurance of FIT; propose a solution to third party internal quality assurance materials and summarise the challenges of standardisation and harmonisation of FIT.

Laboratory screening markers in gastroenterology--state of the art.

INTRODUCTION: Screening tests for gastrointestinal diseases acceptable for population with a high sensitivity and high specificity can now be offered by clinical laboratories. This paper summarizes major recent advances in this area of laboratory medicine. METHODS: Relevant articles published within the last 5 years in the NLM (National Library of Medicine) PubMed - Medline database covering the three gastrointestinal diseases - colorectal cancer, coeliac disease, and atrophic gastritis were included for this overview. RESULTS: In Europe, colorectal cancer (CRCA) is the second most frequent malignant disease. Quantitative immunochemical analysis of the stool for haemoglobin provides the best screening test to date, with both sensitivity and specificity approaching 95%. Even though coeliac disease (CD) affects approximately 1% of the general population, it remains largely unrecognised. Recommended methods for screening currently involve the detection of IgA and IgG antibodies against tissue transglutaminase and deamidated gliadin peptide. Evaluations of screening are now discussed for other diseases of the gastrointestinal tract - such as chronic atrophic gastritis (CAG), and inflammatory bowel disease (IBD). Detection of infection by Helicobacter pylori and stomach-specific plasmatic biomarkers, especially pepsinogen I/II ratio, could help with the prevention of gastric carcinomas. The use of faecal calprotectin as a screening test could substantially reduce the number of invasive methods necessary for the diagnostic work-up of patients with IBD. CONCLUSIONS: Screening tests for CRCA and CD have been used worldwide for many years. Screening strategies for gastrointestinal diseases are suggested in the text, based on recent basic science, clinical papers as well as our own experience.

Improvements in colorectal cancer screening programmes - quantitative immunochemical faecal occult blood testing - how to set the cut-off for a particular population.

OBJECTIVE: The aim of the study was to determine the optimum cut-off value of the quantitative immunochemical test (q-FIT) OC-Sensor for colorectal cancer and advanced adenomatous polyps in a particular population. METHODS: 815 patients were referred for colonoscopy and were offered two q-FIT examinations at two different colonoscopy centers. The patients were classified according to the colonoscopic findings. Test sensitivity, specificity, and accuracy were statistically evaluated using one test and two tests at the levels of 50, 75, 100, 125, and 150 ng/mL of faecal hemoglobin in those patients with advanced polyps and colorectal cancer. The optimum cut-off test level for clinically significant neoplasia was determined using one test. RESULTS: The optimum cut-off value of q-FIT OC-Sensor for the detection of clinically significant neoplasia in our particular population was determined as 75 ng/mL using one test. This value provides an optimum proportion of 73% sensitivity (±95% CI 60.3% - 83.4%) and 90% specificity (±95% CI 86.8% - 92.8%), PPV and NPV were determined as 54.76% and 95.43% respectively. CONCLUSIONS: The first step in the implementation of q-FIT test in the screening program in our country is to determine the optimum cut-off level for a population, and to estimate the number of tests performed with respect to the optimum cost effectiveness and economical climate. Using one test, the optimum level of q-FIT OC-Sensor® in the Czech Republic was determined as 75 ng/mL. This study could serve as a model for further studies in other countries, where screening does not yet exist.

Tissue transglutaminase-serology markers for coeliac disease.

Serology markers of coeliac disease (CD) - antigliadin IgA/IgG antibodies (AGA/AGG) with purified alpha-gliadin, antiendomysium IgA antibodies (EmA) and anti-tissue transglutaminase (atTG) IgA/IgG antibodies--determined in 1451 serum samples, were analysed with respect to different screening algorithms. Determination of atTG using five ELISA methods was compared taking into account the impact of human recombinant antigen and IgG class of atTG. A subgroup of 119 patients undergoing small intestinal biopsy was used to calculate sensitivity and specificity of CD markers. The highest sensitivity (94%) was obtained for AGG, and the highest specificity (93.5%) was obtained for EmA. All coeliac disease patients were detected using the combination of all four CD markers, resulting in 100% sensitivity. CD and type 1 diabetes mellitus autoantigens were determined in 139 diabetic patients. The atTG IgA mean value (16.7 IU/ml) was higher in the antiglutamate dehydrogenase antibody (GAD)-positive subgroup, where at least one CD marker was positive in 83.6% subjects. In the GAD-negative subgroup atTG IgA was 8.73 lU/ml and at least one CD marker was positive in 57.4% subjects. atTG in IgA and IgG classes could be recommended as valuable serological markers of CD in the differential diagnosis of malabsorption as well as in various screening algorithms. ELISA determination of atTG with human antigen could increase the specificity, especially in patients with other autoimmune diseases.