The Calcium Carbonate Breath Test, a noninvasive test of stimulated gastric acid secretion: preliminary communication.
BACKGROUND
Gastric acid secretion is subject to complex control mechanisms, and varies widely between individuals and populations. Its measurement has previously required intubation of the stomach with ingestion of a test meal or injection of a secretion stimulant.


OBJECTIVE
We describe a novel method of measuring gastric acid secretion noninvasively - the Calcium Carbonate Breath Test.


METHODS
13C-labelled calcium carbonate is ingested by a fasting participant. The carbonate neutralizes gastric acid to produce 13CO2, which is expired in the breath. Measurement of the excess 13CO2 in the breath allows back-calculation of the amount of gastric acid secreted during the test, provided that other variables affecting CO2 production and excretion are minimized or controlled for.


RESULTS
Studies on a single healthy individual have shown reproducible estimations of acid secretion and over 80% suppression of acid secretion after the proton pump inhibitor treatment.


CONCLUSIONS
The method seems to be promising, but further studies on other individuals need to be carried out. The Calcium Carbonate Breath Test may have wide applications in epidemiological studies, clinical management of acid-related diseases, screening for hypochlorhydria and development of new acid-suppressing treatments.
Clough
Michael R I
MR
Department of Gastroenterology, The General Infirmary at Leeds, Leeds, UK.
Axon
Anthony T R
AT
D001944:Breath Tests / Q000379:methods*; D002119:Calcium Carbonate / Q000008:administration & dosage; D002245:Carbon Dioxide / Q000032:analysis; D002247:Carbon Isotopes; D004305:Dose-Response Relationship, Drug; D005744:Gastric Acid / Q000378:metabolism*; D005745:Gastric Acidity Determination; D006801:Humans; D009853:Omeprazole / Q000494:pharmacology; D054328:Proton Pump Inhibitors / Q000494:pharmacology
D002247:Carbon Isotopes; D054328:Proton Pump Inhibitors; D002245:Carbon Dioxide; D002119:Calcium Carbonate; D009853:Omeprazole