title: Application of isotope-selective nondispersive infrared spectrometry (IRIS) for evaluation of [13C]octanoic acid gastric-emptying breath tests: comparison with isotope ratio-mass spectrometry (IRMS).
abstract: Suitability of isotope-selective nondispersive infrared spectrometry (IRIS) for evaluation of [13C]octanoic acid gastric-emptying breath test was assessed and compared with standard isotope ratio-mass spectrometry (IRMS). The estimated bias of IRMS and IRIS measurements of baseline-corrected 13CO2 exhalation amounted to +/-0.1 and +/-0.6 delta delta values (n = 360), respectively. In breath tests performed on 60 diabetic patients, the gastric emptying parameters were calculated by nonlinear regression analysis of the time course of 13CO2 exhalation: half-emptying time (t1/2,breath, 90 +/- 39 min), lag phase (tlag,breath, 34 +/- 27 min), and gastric emptying coefficient (GEC, 2.9 +/- 0.5). A reasonable linear correlation was found between the two methods (y = IRIS, x = IRMS) with respect to delta delta values (y = 0.35 + 0.92x, r = 0.985, Sy[symbol: see text]x = +/-0.6, n = 1116) and a rather good agreement of the computed gastric emptying parameters was obtained (t1/2,breath: y = 0.99x + 4.06, Sy[symbol: see text]x = +/- 6.3; tlag, breath: y = 0.97x + 0.96, Sy[symbol: see text]x = +/-3.4; GEC: y = 0.97x - 0.01, Sy[symbol: see text]x = +/-0.09).
authors.affiliation: Diabetes Forschungsinstitut, Klinische Biochemie Auf'm Hennekamp 65, Düsseldorf, Germany. schadewa@uni-duesseldorf.de
authors.forename: P
authors.initials: P
authors.lastname: Schadewaldt
authors.forename: B
authors.initials: B
authors.lastname: Schommartz
authors.forename: G
authors.initials: G
authors.lastname: Wienrich
authors.forename: H
authors.initials: H
authors.lastname: Brösicke
authors.forename: R
authors.initials: R
authors.lastname: Piolot
authors.forename: D
authors.initials: D
authors.lastname: Ziegler
mesh_terms: D000328:Adult; D000959:Antihypertensive Agents; D001944:Breath Tests / Q000379:methods; D002210:Caprylates; D002245:Carbon Dioxide / Q000032:analysis; D002247:Carbon Isotopes; D003920:Diabetes Mellitus / Q000503:physiopathology*; D005260:Female; D005746:Gastric Emptying; D018589:Gastroparesis / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D013055:Spectrophotometry, Infrared / Q000379:methods*
chemical_list: D000959:Antihypertensive Agents; D002210:Caprylates; D002247:Carbon Isotopes; D002245:Carbon Dioxide; C031492:octanoic acid