The urea breath test (UBT) is the most sensitive and specific non-inva
sive test for the detection of Helicobacter pylori infection both befo
re and after treatment, Labelling of the urea with either C-13 or C-14
has relative advantages and disadvantages. C-13-UBTs are both safe an
d well-validated, and have the additional advantage that they can be u
sed in children. However, the initial capital costs of (CO2)-C-13 anal
ysis are large compared to those for (CO2)-C-14. The protocol details
for use of the C-13-UBT are variable: a test meal is important if urea
solution is to be used and a single sample time point at 30 min is ad
equate. The recent development of novel formulations of C-13 urea and
new analytical techniques for the measurement of (CO2)-C-13 should all
ow reduction in the length of the test and its cost; they may herald a
more widespread clinical application of this useful test.