13C-[alpha]-Ketoisocaproic Acid Breath Test Revisited: An In-Depth Reproducibility Study Advocates an Extended Breath Sampling Period

• Published in: Digestive diseases and sciences 2007-12, Vol.52 (12), p.3481
• Main Authors: Kasicka-Jonderko, Anna, Jonderko, Krzysztof, Kaminska, Magdalena, Bielecka, Monika, Blonska-Fajfrowska, Barbara
• Format: Article
• Language: English
• ISSN: 0163-2116; 1573-2568
• DOI: 10.1007/s10620-007-9767-7

In this study we sought for a quantitative parameter which would offer the best reproducibility of a standard 13C-α-ketoisocaproic acid (13C-KICA) breath test. On 3 separate days 14 healthy volunteers (7 females, 7 males) took orally 1 mg/kg body mass 13C-KICA and 20 mg/kg body mass l-leucine. Samples of expiratory air for 13CO2 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 13C recovery (D max), showed an unsatisfactory reproducibility, and the D max displayed a fairly good reproducibility, whereas the cumulative 13C 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 13C recovery appears to be the most reliable parameter of the 13C-KICA breath test. [PUBLICATION ABSTRACT]