Once the diagnosis of peptic ulceration is suspected, the first-
Line investigation of choice is an oesophagogastroduodenoscopy
(OCD), This will allow mucosal inspection of the upper GI tract
lumen, Lesser curve ulceration is the most common site within
the stomach, but duodenal ulceration is more common overall
and most frequently seen in the 1st part of the duodenum. During
the endoscopic procedure consideration should be given to the
detection of H. pylori within the stomach. The diagnosis of its
presence can be achieved in several ways, detailed in Table Z,
but most common is a rapid urease test performed by placing
a tissue biopsy from the gastric antrum into a small well of a pH-
sensitive gel containing urea. If H. pylori organisms are present,
the urease enzyme breaks down the urea to form alkaline
ammonium ions that lead to a rise in pH Within the gel and
a corresponding change in colour. Of the non-invasive tests, the
urea breath test once again exploits the ability of H. pylori to
metabolize urea into more basic components. Briefly, the patient
drinks a solution containing a known quantity of 13C- or 14C-
radiolabelled urea. in the presence of viable H. pylori organisms,