Chemical testing for drugs: what it is, how it works
| Author | Nathan Baker |
| Pages | 31-52 |
CHAPTER
3
Chemical
Testing
for
Drugs:
What
It
Is,
How
It
Works
Section
254(3.4)
of
the
Criminal
Code
of
Canada
provides:
(3.4)
If,
on
completion
of
the
evaluation,
the
evaluating
officer
has
rea
sonable
grounds
to
believe,
based
on
the
evaluation,
that
the
person
’
s
ability
to
operate
a
motor
vehicle,
a
vessel,
an
aircraft
or
railway
equip
ment
is
impaired
by
a
drug
or
by
a
combination
of
alcohol
and
a
drug,
the
evaluating
officer
may,
by
demand
made
as
soon
as
practicable,
require
the
person
to
provide,
as
soon
as
practicable,
(a)
a
sample
of
either
oral
fluid
or
urine
that,
in
the
evaluating
offi
cer
’
s
opinion,
will
enable
a
proper
analysis
to
be
made
to
determine
whether
the
person
has
a
drug
in
their
body;
or
(b)
samples
of
blood
that,
in
the
opinion
of
the
qualified
medical
practi
tioner
or
qualified
technician
taking
the
samples,
will
enable
a
proper
analysis
to
be
made
to
determine
whether
the
person
has
a
drug
in
their
body.
There
are
three
bodily
samples,
oral
fluid
(saliva),
urine,
and
blood,
which
can
be
taken
from
a
person
under
investigation.
They
will
each
be
examined
in
this
chapter.
Each
of
these
can
be
taken
in
different
meth
ods
and
then
tested
in
different
ways.
The
manner
in
which
they
are
taken
and
the
method
used
for
testing
will
affect
the
reasonableness
of
the
search
undertaken,
the
probative
value
of
the
tests,
and
the
weight
that
a
trier-of-fact
can
give
to
the
tests.
31
DRUG-IMPAIRED
DRIVING
IN
CANADA
Chain
of
custody
relating
to
bodily
samples
is
important
for
the
Crown,
not
only
in
ensuring
that
the
expert
opinion
relating
to
testing
can
be
relied
upon,
but
also
in
ensuring
the
privacy
interest
of
an
accused.
Determining
who
took
the
sample,
how,
when,
and
under
what
conditions
will
ensure
that
the
sample
can
be
relied
upon
forensically
to
provide
probative
information.
Eliminating
issues
surrounding
contamination,
proper
storage,
time
to
testing,
and
proper
transportation
to
the
testing
laboratory
will
be
important
to
ensuring
conviction.
ORAL
FLUID
TESTING
Oral
fluid
means
saliva.
Saliva
testing
is
one
of
the
less
intrusive
methods
to
enable
testing
for
drugs
in
an
individual.
Although
it
does
require
the
close
monitoring
similar
to
urine
sampling
to
ensure
an
unadulterated
sample,
it
does
not
invade
the
privacy
in
the
same
way
that
observing
a
person
urinating
does,
nor
does
it
interfere
with
the
bodily
integrity
of
the
individual
in
the
same
way
as
blood
testing.
While
certainly
more
intrusive
than
a
breath
sample,
it
has
many
hallmarks
of
concern
in
com
mon
with
breath
testing,
such
as
the
sanitary
method
in
which
samples
are
taken.
The
issue
of
saliva
testing
comes
down
to
limits
on
the
tech
nology
available
to
police.
The
most
common
form
of
saliva
testing
is
to
use
an
immunoassay
screening
process.
This
uses
a
form
of
enzyme
that
reacts
to
the
drug
compound
in
the
saliva
to
create
a
reaction.
This
is
often
seen
through
a
strip
that
changes
colour,
or
in
new
testing
methods
through
a
machine
that
provides
a
digital
reading.
This
form
of
testing
is
prone
to
false
posi
tives,
which
is
an
obvious
concern
when
using
such
tests
as
evidence
in
a
criminal
matter.
Most
oral
fluid
testing
can
only
detect
a
class
of
drug
and
not
a
particular
drug;
for
example,
it
will
indicate
opioids
but
not
the
kind,
such
as
oxycodone,
morphine,
or
some
other
particular
drug.
The
advan
tage
of
saliva
or
oral
fluid
testing
is
that
it
can
show
present
exposure
to
a
drug,
because
drug
compounds
in
blood
are
also
seen
in
the
saliva.
In
addition
to
this,
there
is
no
need
for
the
drug
to
be
processed
through
the
body
to
waste
as
in
the
case
of
urine
testing.
Oral
consumption,
including
smoking,
can
lead
to
false
positives
due
to
samples
of
the
drug
being
left
in
the
oral
cavity,
but
for
only
a
short
time
after
consumption.
Given
the
32
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