Tohoku J. Exp. Med., 2014 April, 232(4)

Calcium Carbonate Breath Test for Non-Invasive Estimation of Gastric Acid Secretion

HIROHIKO SHINKAI,¹ KATSUNORI IIJIMA,¹ TOMOYUKI KOIKE,¹ KENICHIRO NAKAGAWA,¹ RYUHEI MAEJIMA,¹ HIROYUKI ENDO,¹ NOBUYUKI ARA,¹ NAOKI ASANO,¹ AKIRA IMATANI,¹ SHUICHI OHARA² and TOORU SHIMOSEGAWA¹

¹Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
²Department of Gastroenterology, Tohoku Rosai Hospital, Sendai, Miyagi, Japan

Gastric acid measurement is useful in assessing the effectiveness of antisecretory drugs, however, the conventional tests involve invasive nasogastric intubation. Orally administered ¹³C-labeled calcium carbonate (Ca¹³CO₃) reacts with gastric acid to produce ¹³C-labeled carbon dioxide (¹³CO₂), which is then excreted in the breath. The objective of this study was to evaluate the suitability of Ca¹³CO₃ breath test for estimating gastric acid secretion in human noninvasively. First, the Ca¹³CO₃ breath test and the measurement of pooled gastric acid under a fasting condition were performed in 6 healthy volunteers to evaluate the correlation between the two parameters. Next, endoscopic gastric acid collection and the Ca¹³CO₃ breath test were performed on different days after pentagastrin injection in 20 subjects to evaluate the correlation between the tests and the reproducibility. Finally, the same studies were repeated in 4 subjects before and after 1-week rabeprazole, a proton pump inhibitor, administration. The maximum ¹³CO₂ concentration (Cmax) correlated very well with the amount of pooled gastric acid (r = 0.95), suggesting that Ca¹³CO₃ breath test values well reflected the fasting intragastric acidity. The ¹³CO₂ concentration after pentagastrin injection correlated well with pentagastrin-stimulated maximal acid output (r = 0.79 at 20 min). The reproducibility of the Ca¹³CO₃ breath test under pentagastrin-stimulation was good (coefficient of variation = 0.11). Rabeprazole administration markedly reduced the values of the Ca¹³CO₃ breath test, suggesting that it can sensitively assess the efficacy of rabeprazole. The Ca¹³CO₃ breath test can potentially be a useful method for non-invasive estimation for gastric acid secretion in human.

keywords —— breath test; ¹³C-labeled calcium carbonate; gastric acid secretion; gastro-esophageal reflux disease; proton pump inhibitor

© 2014 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2014, 232, 255-261

Correspondence: Katsunori Iijima, M.D., Division of Gastroenterology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8574, Japan.

e-mail: kiijima@med.tohoku.ac.jp