Ring
Test
The
ring
test
is
a
widely
used
qualitative
test
for
demonstrating
precipitation.
In
a
small
test
tube
a
layer
of
antigen
solution
is
carefully
placed
over
the
solution
of
an
antiserum.
Diffusion
of
the
antigen
and
antibody
establishes
a
layer
of
optimal
proportion.
Within
a
few
minutes
a
ring
of
precipitate
forms
at
the
interface
between
the
two
solutions.
This
is
a
rapid
method
of
detecting
and
identifying
an
unknown
antigen
or
antibody.
