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Detection
of Abused Drugs in Oral Fluid
E.P.
Schoener, S. Doddamane, S. Kardos*, and R.S. Niedbala*
Wayne State Univ, Detroit, MI, *STC Technologies, Bethlehem,
PA
ABSTRACT
While
objective tests for psychotropic substances have been adopted
widely as tools for treatment, forensics and workplace,
those currently in use are intrusive. Tests on saliva would
be more acceptable and more convenient than those based
on blood, urine and hair specimens. Before we implement
tests on oral fluid, however, it is necessary to determine
their validity and concordance with accepted techniques
under ‘real world’ conditions. The present study compared
detection of cocaine, amphetamines, opiates, marijuana,
PCP, barbiturates, benzodiazepines, propoxyphene, methaqualone,
and methadone in saliva and urine specimens from 57 clients
in a treatment program and 22 controls. The client group
was comprised of 31 men (Avg age = 48.2 +/- 8.7) and 26
women (46.4 +/- 8.2). The control group was evenly divided
between men (36.4 +/- 11.3) and women (37.7 +/- 8.3). All
participants were asked confidentially to report their use
of medications and illicit substances over the past week.
Specimens were provided weekly for up to 16 weeks (Avg 8.5
+/- 4.5). Urine was collected by conventional methods and
oral fluid was obtained with an Orasure® device (Epitope,
Inc., Portland, OR). Samples were tested for IgG as a control
measure. 702 matched oral/urine specimens were submitted
to standard immuno-assay procedure and reported qualitatively.
All urine and saliva positives were confirmed with GC/MS.
Findings with both specimens were not always concordant
due to differences in pharmacokinetic distribution.
INTRODUCTION
Over
the past generation, the growing concern about substance
abuse has inspired considerable research on the etiologic
and pathogenetic mechanisms of addiction. New intervention
tools also have been introduced, including drug testing
in various biological tissues/fluids. While hair, skin patch,
finger nails and meconium have been employed, urine and
blood remain the most common media. All of these have significant
limitations and it has been proposed that oral fluids could
provide an excellent alternative to detect many drugs of
abuse. Oral fluid (‘saliva’) can be collected easily and
non-invasively, precluding patient risk and the opportunity
for adulteration. While analyte concentration predictably
is low in oral fluid, current methods have sufficient sensitivity
and specificity for valid measurement. A great advantage
of saliva concentration is that it may reflect closely the
blood level of parent drugs. It is important to note, however,
that appearance of a drug in saliva is dependent upon its
physical, chemical and pharmacological attributes (S/P ratio).
If we
are to capitalize on the advantages of oral fluid testing,
we must validate saliva levels against those we obtain using
common test methods under ‘real life’ conditions. Therefore,
the present study sought to examine the relationship between
concentrations of abused drugs in oral fluid and urine among
clients in a methadone maintenance program.
METHODS
Clients
attending a methadone maintenance program, and staff volunteers
(‘controls’) were invited to participate in this study.
After learning that we wished to collect oral fluids and
urine from them confidentially on a weekly basis for up
to 16 weeks, and signing the Informed Consent, participants
were enrolled. Each week, we reserved an aliquot of their
regular “drop” and asked them to place two cellulose pads
(Intercept™ Oral Specimen Collection Device) on either
side of their mouth between the lower gum and cheek for
2-5 min. At this time they completed a confidential assessment
of their drug use over the past week, including medications
and over-the-counter drugs. Each pad was placed in a separate
vial with preservative and sealed. Both urine and oral fluid
samples were stored at 0°C and shipped to the STC Diagnostics
laboratory within two days for analysis. Participants received
limited financial compensation for their cooperation.
STC
technicians performed all of the screening and confirmatory
assays in their own facilities. Urine specimens were screened
for amphetamine, methamphetamine, cocaine, opiates, methadone,
THC, PCP, propoxephene, barbiturates, and benzodiazepines
with the commercially-available EMIT assay, using standard
cutoff values (see Table). Confirmatory tests were conducted
on all positive samples with GC/MS. Oral fluids expressed
from the cellulose pads were screened for the same substances
using the STC MICRO-PLATE EIA (a competitive immunoassay).
All were tested for IgG as well to assure sample adequacy.
A random sample of the positive specimens have been tested
for confirmation using GC/MS/MS.
RESULTS
A demographically
well-balanced group of clients and staff agreed to participate
in this study (see Table), although many clients and some
staff were unable to complete the entire 16 weeks. The mean
number of specimens provided by all participants was 8.5
+/- 4.5 (range 1-17). Approximately equal numbers of women
and men took part. While the control group tended to be
younger than the experimental group, men and women in each
were about the same age. Female staff members were the most
cooperative in that they provided more specimens than their
male counterparts.
A single
participant’s data are presented in the untitled spreadsheet
that follows. Note that this individual frequently reported
having used several drugs over the past week, but on occasion
included some that were not identified by assay or excluded
others that were.
Comparison
of the participants’ self report data with urine screens
revealed some interesting differences between the clients
and controls. Virtually all of the controls showed total
agreement of the two (SR = U). However, approximately equal
numbers of the clients accurately or underreported (˜40%)
and the balanced over-reported their use (or otherwise went
undetected). Confirmatory (GC/MS) assay of urine screen
data showed a very high degree of complementarity (> 80%Scr
= Conf) among the clients. The small number of staff positives
were also confirmed. None of the negative screens were submitted
to GC/MS assay (indicated as N/A).
Ultimate
comparison of urine and oral fluid specimen data to date
indicates a very high degree of agreement between the two
(˜ 84%). Interestingly, while all of the specimens found
positive by urine assay were also positive in saliva, the
opposite was not found to be true. Analyses are still in
progress.
Graphs
and Tables
Assay
Cutoff Values
Participants
Self
Report: Urine Screen Agreement
General
Chart
Urine
Screen: Confirm Agreement
Urine:
Oral Agreement
Comparison
of Assays
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