title: 13C-alpha-Ketoisocaproic acid breath test revisited: an in-depth reproducibility study advocates an extended breath sampling period.
abstract: In this study we sought for a quantitative parameter which would offer the best reproducibility of a standard (13)C-alpha-ketoisocaproic acid ((13)C-KICA) breath test. On 3 separate days 14 healthy volunteers (7 females, 7 males) took orally 1 mg/kg body mass (13)C-KICA and 20 mg/kg body mass L-leucine. Samples of expiratory air for (13)CO(2) measurement with the use of isotope ratio mass spectrometry were collected every 5 min during the first hour and then at 70, 80, 90, 105, 120, 150, 180, 240, 300, 360, 540, 720, and 1440 min. Short-term reproducibility assessment involved paired examinations taken 3.5 days apart; paired examinations separated by 22 days (median) served for the medium-term reproducibility assessment. T(max), the time to reach the maximum momentary (13)C recovery (D(max)), showed an unsatisfactory reproducibility, and the D(max) displayed a fairly good reproducibility, whereas the cumulative (13)C recovery calculated for a time span within the range 0-90 and 0-120 min exhibited the best reproducibility. In no case did the medium-term reproducibility prove any worse than the short-term one. Taking into account its reproducibility, the cumulative (13)C recovery appears to be the most reliable parameter of the (13)C-KICA breath test.
authors: Department of Basic Biomedical Science, School of Pharmacy, Medical University of Silesia, Kasztanowa Street 3, PL-41-205 Sosnowiec, Poland. akj@slam.katowice.pl
authors: Anna
authors: A
authors: Kasicka-Jonderko
authors: Krzysztof
authors: K
authors: Jonderko
authors: Magdalena
authors: M
authors: Kamińska
authors: Monika
authors: M
authors: Bielecka
authors: Barbara
authors: B
authors: Błońska-Fajfrowska
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000388:Air / Q000032:analysis*; D001944:Breath Tests / Q000379:methods; D002208:Caproates; D002247:Carbon Isotopes / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007651:Keto Acids / Q000008:administration & dosage; D008099:Liver / Q000378:metabolism; D008297:Male; D013058:Mass Spectrometry; D015203:Reproducibility of Results
chemical_list: D002208:Caproates; D002247:Carbon Isotopes; D007651:Keto Acids; C013082:alpha-ketoisocaproic acid