1
|
Nichols BL, Baker RD, Baker SS. Overview of Breath Testing in Clinical Practice in North America. JPGN REPORTS 2021; 2:e027. [PMID: 37206939 PMCID: PMC10191541 DOI: 10.1097/pg9.0000000000000027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 06/29/2020] [Indexed: 05/21/2023]
Abstract
Human breath is an easily, noninvasively obtained substance. It offers insight into metabolism and is used to diagnose disaccharide malabsorption, infection, small bowel bacterial over growth, and transit times. Herein, we discuss the readily available clinical breath tests, how they function, how they are administered and interpreted and some pitfalls in their use.
Collapse
Affiliation(s)
- Buford L. Nichols
- From the Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX
| | - Robert D. Baker
- Department of Pediatrics, University at Buffalo, Buffalo, NY
| | - Susan S. Baker
- Department of Pediatrics, University at Buffalo, Buffalo, NY
| |
Collapse
|
2
|
Holzhütter HG, Wuensch T, Gajowski R, Berndt N, Bulik S, Meierhofer D, Stockmann M. A novel variant of the 13C-methacetin liver function breath test that eliminates the confounding effect of individual differences in systemic CO 2 kinetics. Arch Toxicol 2020; 94:401-415. [PMID: 32020249 DOI: 10.1007/s00204-020-02654-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 01/27/2020] [Indexed: 12/23/2022]
Abstract
The principle of dynamic liver function breath tests is founded on the administration of a 13C-labeled drug and subsequent monitoring of 13CO2 in the breath, quantified as time series delta over natural baseline 13CO2 (DOB) liberated from the drug during hepatic CYP-dependent detoxification. One confounding factor limiting the diagnostic value of such tests is that only a fraction of the liberated 13CO2 is immediately exhaled, while another fraction is taken up by body compartments from which it returns with delay to the plasma. The aims of this study were to establish a novel variant of the methacetin-based breath test LiMAx that allows to estimate and to eliminate the confounding effect of systemic 13CO2 distribution on the DOB curve and thus enables a more reliable assessment of the hepatic detoxification capacity compared with the conventional LiMAx test. We designed a new test variant (named "2DOB") consisting of two consecutive phases. Phase 1 is initiated by the intravenous administration of 13C-bicarbonate. Phase 2 starts about 30 min later with the intravenous administration of the 13C-labelled test drug. Using compartment modelling, the resulting 2-phasic DOB curve yields the rate constants for the irreversible elimination and the reversible exchange of plasma 13CO2 with body compartments (phase 1) and for the detoxification and exchange of the drug with body compartments (phase 2). We carried out the 2DOB test with the test drug 13C-methacetin in 16 subjects with chronic liver pathologies and 22 normal subjects, who also underwent the conventional LiMAx test. Individual differences in the systemic CO2 kinetics can lead to deviations up to a factor of 2 in the maximum of DOB curves (coefficient of variation CV ≈ 0.2) which, in particular, may hamper the discrimination between subjects with normal or mildly impaired detoxification capacities. The novel test revealed that a significant portion of the drug is not immediately metabolized, but transiently taken up into a storage compartment. Intriguingly, not only the hepatic detoxification rate but also the storage capacity of the drug, turned out to be indicative for a normal liver function. We thus used both parameters to define a scoring function which yielded an excellent disease classification (AUC = 0.95) and a high correlation with the MELD score (RSpearman = 0.92). The novel test variant 2DOB promises a significant improvement in the assessment of impaired hepatic detoxification capacity. The suitability of the test for the reliable characterization of the natural history of chronic liver diseases (fatty liver-fibrosis-cirrhosis) has to be assessed in further studies.
Collapse
Affiliation(s)
- Hermann-Georg Holzhütter
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Biochemistry, Computational Systems Biochemistry Group, Charitéplatz 1, 10117, Berlin, Germany.
| | - Tilo Wuensch
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Surgery, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Robert Gajowski
- Max Planck Institute of Molecular Genetics, Mass Spectroscopy Facility, Ihnestraße 63-73, 14195, Berlin, Germany
- Department of Biology, Chemistry, and Pharmacy, Free University Berlin, Takustraße 3, 14195, Berlin, Germany
| | - Nikolaus Berndt
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Biochemistry, Computational Systems Biochemistry Group, Charitéplatz 1, 10117, Berlin, Germany
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute for Computational and Imaging Science in Cardiovascular Medicine, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Sascha Bulik
- Federal Institute of Risk Assessment, Diedersdorfer Weg 1, 12277, Berlin, Germany
| | - David Meierhofer
- Max Planck Institute of Molecular Genetics, Mass Spectroscopy Facility, Ihnestraße 63-73, 14195, Berlin, Germany
| | - Martin Stockmann
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Surgery, Augustenburger Platz 1, 13353, Berlin, Germany
| |
Collapse
|