<s>
Esophagogastroduodenoscopy	B-Application
(	O
EGD	O
)	O
or	O
oesophagogastroduodenoscopy	B-Application
(	O
OGD	O
)	O
,	O
also	O
called	O
by	O
various	O
other	O
names	O
,	O
is	O
a	O
diagnostic	O
endoscopic	B-Application
procedure	O
that	O
visualizes	O
the	O
upper	O
part	O
of	O
the	O
gastrointestinal	O
tract	O
down	O
to	O
the	O
duodenum	O
.	O
</s>
<s>
The	O
words	O
esophagogastroduodenoscopy	B-Application
(	O
EGD	O
;	O
American	O
English	O
)	O
and	O
oesophagogastroduodenoscopy	B-Application
(	O
OGD	O
;	O
British	O
English	O
;	O
see	O
spelling	O
differences	O
)	O
are	O
both	O
pronounced	O
.	O
</s>
<s>
It	O
is	O
also	O
called	O
panendoscopy	B-Application
(	O
PES	O
)	O
and	O
upper	B-Application
GI	I-Application
endoscopy	I-Application
.	O
</s>
<s>
It	O
is	O
also	O
often	O
called	O
just	O
upper	B-Application
endoscopy	I-Application
,	O
upper	O
GI	O
,	O
or	O
even	O
just	O
endoscopy	B-Application
;	O
because	O
EGD	O
is	O
the	O
most	O
commonly	O
performed	O
type	O
of	O
endoscopy	B-Application
,	O
the	O
ambiguous	O
term	O
endoscopy	B-Application
is	O
sometimes	O
informally	O
used	O
to	O
refer	O
to	O
EGD	O
by	O
default	O
.	O
</s>
<s>
The	O
term	O
gastroscopy	B-Application
literally	O
focuses	O
on	O
the	O
stomach	O
alone	O
,	O
but	O
in	O
practice	O
,	O
the	O
usage	O
overlaps	O
.	O
</s>
<s>
Problems	O
of	O
gastrointestinal	O
function	O
are	O
usually	O
not	O
well	O
diagnosed	O
by	O
endoscopy	B-Application
since	O
motion	O
or	O
secretion	O
of	O
the	O
gastrointestinal	O
tract	O
is	O
not	O
easily	O
inspected	O
by	O
EGD	O
.	O
</s>
<s>
Nonetheless	O
,	O
findings	O
such	O
as	O
excess	O
fluid	O
or	O
poor	O
motion	O
of	O
the	O
gut	O
during	O
endoscopy	B-Application
can	O
be	O
suggestive	O
of	O
disorders	O
of	O
function	O
.	O
</s>
<s>
Often	O
inspection	O
alone	O
is	O
sufficient	O
,	O
but	O
biopsy	O
is	O
a	O
valuable	O
adjunct	O
to	O
endoscopy	B-Application
.	O
</s>
