13
C-Breath tests for assessment
of gastrointestinal disorders and
liver function
exhaled breath after ingestion of a
stable
13
C isotope labelled substance
and its subsequent metabolism with
a specific function (e.g. gastric emp-
tying) or enzyme as a rate limiting
step. Breath samples are collected
and analysed, for example, with an
IRIS
®
analyser, measuring the stage
between ingestion by the patient of
the labelled substance and its ap-
pearance in the exhaled breath.
The
13
C breath test offers following
benefits:
•
It is a patient-friendly diagnostic
test
•
The test is non-invasive and does
not involve ionising radiation
•
There are no side effects and the
test can be repeated at any time
•
The test allows for in vivo analy-
sis of enzyme activity and gastric
physiology, can be performed
anywhere and the samples can be
sent for central analysis.
•
It produces rapid results
The reference method for determin-
ing gastric emptying of solid and liq-
uid nutrients is functional scintigra-
phy with radioactively labelled test
meals. However, the usefulness of
this method is limited due to radio-
active hazard and protection require-
ments, the need for a gamma cam-
era and the long time it takes.
Apart from the diagnosis of Heli-
cobacter pylori infections, the
13
C
breath test also enables the quanti-
tative diagnosis of enzyme activity,
organ function and gastrointestinal
transport processes.
According to PD Dr. Oliver Götze,
consultant gastroenterologist and
head of the functional GI laboratory
of the University Hospital, Zurich,
these include
13
C octaonic acid and
13
C acetate tests for measurement
of gastric emptying and quantitative
analysis of liver function.
These in general, stable isotope tests
measure increased levels of
13
CO
2
in
5
13
C-Breath tests for assessment of gastrointestinal disorders and liver function
13
C breath test for measuring gastric emptying
Measurement of base value in
exhaled air (normal: - 26‰)
Parameters for gastric emptying
***
Mathematical computation of
curve by linear regression
Processes after
emptying
13
CO
2
-exhalation
Test meal +
13
C marker
Goetze et al.: Neurogastroenterol Motil 2009
Kuyumcu & Goetze: Gastroenterologe 2011
* solid test meals
** liquid test meals
*** Half empyting time (T
50
) and lag time
(time to onset of gastric emptying)
13
C octanoic acid
*
13
C acetate
**
1,2,3,4 6,7,8