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Clinical Drug
Testing in
Primary Care
Technical Assistance Publication Series
TAP 32Clinical Drug Testing in
Primary Care
TAP
Technical Assistance Publication Series
32
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
Substance Abuse and Mental Health Services Administration
Center for Substance Abuse Treatment
1 Choke Cherry Road
Rockville, MD 20857Clinical Drug Testing in Primary Care
Acknowledgments Electronic Access and Copies
This publication was prepared for the of Publication
Substance Abuse and Mental Health This publication may be ordered from
Services Administration (SAMHSA), by SAMHSA’s Publications Ordering Web page
RTI International and completed by the at http://store.samhsa.gov. Or, please call
Knowledge Application Program (KAP), SAMHSA at 1-877-SAMHSA-7 (1-877-726
contract numbers 270-04-7049 and 270 4727) (English and Español). The document
09-0307, a Joint Venture of The CDM may be downloaded from the KAP Web site at
Group, Inc., and JBS International, Inc., http://kap.samhsa.gov.
with SAMHSA, U.S. Department of Health
and Human Services (HHS). Christina
Currier served as the Contracting Officer’s
Representative.
Recommended Citation
Substance Abuse and Mental Health Services
Administration. Clinical Drug Testing
Disclaimer in Primary Care. Technical Assistance
Publication (TAP) 32. HHS Publication No.
The views, opinions, and content of this (SMA) 12-4668. Rockville, MD: Substance
publication are those of the authors and do Abuse and Mental Health Services
not necessarily reflect the views, opinions, or Administration, 2012.
policies of SAMHSA or HHS.
Originating Office
Public Domain Notice
Quality Improvement and Workforce
All materials appearing in this publication Development Branch, Division of Services
except those taken from copyrighted Improvement, Center for Substance Abuse
sources are in the public domain and may Treatment, Substance Abuse and Mental
be reproduced or copied without permission Health Services Administration, 1 Choke
from SAMHSA. Citation of the source is Cherry Road, Rockville, MD 20857.
appreciated. However, this publication may
not be reproduced or distributed for a fee HHS Publication No. (SMA) 12-4668
without the specific, written authorization Printed 2012
of the Office of Communications, SAMHSA,
HHS.
iiContents
Chapter 1—Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Audience for the TAP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Organization of the TAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Reasons To Use Clinical Drug Testing in Primary Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Primary Care and Substance Use Disorders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Development of Drug Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Workplace Drug Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Drug Testing in Substance Abuse Treatment and Healthcare Settings . . . . . . . . . . . . . . 5
Differences Between Federal Workplace Drug Testing and Clinical Drug Testing. . . . . . 6
Caution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Chapter 2—Terminology and Essential
Concepts in Drug Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Drug Screening and Confirmatory Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Testing Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Test Reliability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Window of Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Cutoff Concentrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Cross-Reactivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Drug Test Panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Test Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Point-of-Care Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Adulterants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Specimen Validity Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
iiiClinical Drug Testing in Primary Care
Chapter 3—Preparing for Drug Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Deciding Which Drugs To Screen and Test For . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Choosing a Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Specimen Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Oral Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Sweat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Blood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Hair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Breath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Meconium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Selecting the Initial Testing Site: Laboratory or Point-of-Care . . . . . . . . . . . . . . . . . . . . 23
Collection Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Laboratory Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Advantages and Disadvantages of Testing in a Laboratory . . . . . . . . . . . . . . . . . . . . 25
Considerations for Selecting a Laboratory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Point-of-Care Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Advantages and Disadvantages of POCTs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Considerations for Selecting POCT Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Implementing Point-of-Care Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Preparing Clinical and Office Staffs for Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Preparing a Specimen Collection Site. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Chapter 4—Drug Testing in Primary Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Uses of Drug Testing in Primary Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Monitoring Prescription Medication Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Management of Chronic Pain With Opioids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Evaluation of Unexplained Symptoms or Unexpected Responses to Treatment . . . . 32
Patient Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
ivContents
Pregnancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Psychiatric Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Monitoring Office-Based Pharmacotherapy for Opioid Use Disorders . . . . . . . . . . . . 34
Detection of Substance Use Disorders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Initial Assessment of a Person With a Suspected SUD . . . . . . . . . . . . . . . . . . . . . . . . 35
Talking With Patients About Drug Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Cultural Competency and Diversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Monitoring Patients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Patients With an SUD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Monitoring Patients Receiving Opioids for Chronic Noncancer Pain . . . . . . . . . . . . . 41
Ensuring Confidentiality and 42 CFR Part 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Preparing for Implementing Drug Testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Collecting Specimens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Conducting POCTs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Interpreting Drug Test Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Result: Negative Specimen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Result: Positive Specimen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Result: Adulterated or Substituted Specimen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Result: Dilute Specimen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Result: Invalid Urine Specimen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Frequency of Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Documentation and Reimbursement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Reimbursement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Chapter 5—Urine Drug Testing for Specific Substances . . . . . . . . . . . . . . . . . . . . 51
Window of Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Specimen Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
vClinical Drug Testing in Primary Care
Adulteration, Substitution, and Dilution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Adulteration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Substitution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Dilute Specimens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Cross-Reactivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Alcohol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Amphetamines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Barbiturates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Benzodiazepines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Cocaine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Marijuana/Cannabis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Opioids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Other Substances of Abuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
PCP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Club Drugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
LSD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Inhalants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Appendix A—Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Appendix B—Laboratory Initial Drug-Testing Methods . . . . . . . . . . . . . . . . . . . . 71
Appendix C—Laboratory Confirmatory Drug-Testing Methods . . . . . . . . . . . . . . 73
Appendix D—Laboratory Specimen Validity-Testing Methods . . . . . . . . . . . . . . 75
Appendix E—Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Appendix F—Expert Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Appendix G—Consultants and Field Reviewers . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Appendix H—Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
viExhibits
Exhibit 1-1. U.S. Department of Health and Human Services
Federal Mandatory Workplace Guidelines Cutoff Concentrations
for Initial and Confirmatory Drug Tests in Urine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Exhibit 1-2. Comparison of Federal Workplace
Drug Testing and Clinical Drug Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Exhibit 2-1. Window of Detection for Various Matrices . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Exhibit 3-1. Advantages and Disadvantages
of Different Matrices for Drug Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Exhibit 3-2. Comparison of Laboratory Tests and POCTs . . . . . . . . . . . . . . . . . . . . . . . . 24
Exhibit 3-3. Federal and State Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Exhibit 4-1. Motivational Interviewing Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Exhibit 4-2. The CAGE-AID Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Exhibit 4-3. Brief Intervention Elements: FRAMES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Exhibit 4-4. Patient Flow Through Screening
and Referral in Primary Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Exhibit 5-1. Barbiturates—Window of Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Exhibit 5-2. Benzodiazepines—Window of Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Exhibit 5-3. Opioids—Window of Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
viiChapter 1—Introduction
Audience for the TAP
In This Chapter
This Technical Assistance Publication (TAP), Clinical Drug
• Audience for the Tap Testing in Primary Care, is for clinical practitioners—
• Organization of the physicians, nurse practitioners, and physician assistants—
Tap who provide primary care in office settings and community
health centers. The publication provides information that
• Reasons To Use practitioners need when deciding whether to introduce drug
Clinical Drug Testing testing in their practices and gives guidance on implementing
in Primary Care drug testing.
• Primary Care and
The TAP does not address drug testing for law enforcement
Substance Use
or legal purposes, nor does it include testing for the use of
Disorders
anabolic steroids or performance-enhancing substances.
• Development of Drug This TAP describes some of the ways that drug testing can
Testing contribute to the assessment, diagnosis, and treatment
of patients seen in primary care, the management of the
• Workplace Drug
treatment of chronic pain, and the identification and
Testing
treatment of substance use disorders.
• Drug Testing in
Substance Abuse
Treatment and Organization of the TAP
Healthcare Settings
This chapter briefly describes the role of drug testing in
• Differences Between primary care settings and its historical roots in workplace
Federal Workplace testing. Chapter 2 defines the terms and practices used in
and Clinical Drug drug testing. Chapter 3 presents the mechanics of testing
Testing and describes the steps that primary care practitioners can
• Caution take to prepare themselves, their staffs, and their office
spaces for drug testing. Chapter 4 provides information
about implementing testing in clinical practice. Important
aspects of urine drug testing for specific drugs are presented
in Chapter 5. Appendices A–H include the bibliography;
overviews of technical information on specific tests used
for initial or screening tests, confirmatory tests, and
specimen validity tests; a glossary of terms; the members
of the expert panel, consultants, and field reviewers; and
acknowledgments.
1Clinical Drug Testing in Primary Care
Reasons To Use Clinical Drug • Can affect clinical decisions about
Testing in Primary Care pharmacotherapy, especially with
controlled substances.
The term drug testing can be confusing
because it implies that the test will detect • Increases the safety of prescribing
the presence of all drugs. However, drug medications by identifying the potential for
tests target only specific drugs or drug overdose or serious drug interactions.
classes and can detect substances only • Helps clinicians assess patient use of
when they are present above predetermined opioids for chronic pain management or
thresholds (cutoff levels). The term drug compliance with pharmacotherapy for
screening can also be deceptive because it opioid maintenance treatment for opioid
is often used to describe all types of drug use disorders.
testing. However, drug screening is usually
used in forensic drug testing to refer to the • Helps the clinician assess the efficacy of
use of immunoassay tests to distinguish the treatment plan and the current level
specimens that test negative for a drug and/or of care for chronic pain management and
metabolite from positive specimens. For the substance use disorders (SUDs).
purpose of this TAP, the term drug testing is • Prevents dangerous medication
used. interactions during surgery or other
medical procedures.
When used appropriately, drug testing can
be an important clinical tool in patient care. • Aids in screening, assessing, and
The types of clinical situations in which diagnosing an SUD, although drug testing
clinical drug testing can be used include is not a definitive indication of an SUD.
pain management with opioid medications,
• Identifies women who are pregnant, or who
office-based opioid treatment, primary
want to become pregnant, and are using
care, psychiatry, and other situations when
drugs or alcohol.
healthcare providers need to determine
alcohol or other substance use in patients. • Identifies at-risk neonates.
Drug testing is also used to monitor patients’
• Monitors abstinence in a patient with a
prescribed medications with addictive
known SUD.
potential. Patients sometimes underreport
drug use to medical professionals (Chen, • Verifies, contradicts, or adds to a patient’s
Fang, Shyu, & Lin, 2006), making some self-report or family member’s report of
patients’ self-reports unreliable. Drug substance use.
test results may provide more accurate
information than patient self-report. • Identifies a relapse to substance use.
Although drug testing can be a useful tool
for making clinical decisions, it should not be
the only tool. When combined with a patient’s Primary Care and Substance Use
history, collateral information from a spouse Disorders
or other family member (obtained with
Practitioners can use drug testing to help
permission of the patient), questionnaires,
monitor patients’ use of prescribed scheduled
biological markers, and a practitioner’s
medications, as part of pharmacovigilance,
clinical judgment, drug testing provides
and to help identify patients who may need
information that:
an intervention for SUDs.
• Can affect clinical decisions on a patient’s
For the purpose of this TAP, substances
substance use that affects other medical
refers to alcohol and drugs that can be
conditions.
abused. As defined by the Diagnostic and
Statistical Manual of Mental Disorders,
2Chapter 1―Introduction
Fourth Edition, Text Revision (DSM diagnosed with SUDs. Moreover, the number
IV-TR; American Psychiatric Association of people ages 12 or older seeking help for
[APA], 2000), a substance-related disorder SUDs from a doctor in private practice
is a disorder related to the consumption of increased from 460,000 in 2005 to 672,000 in
alcohol or of a drug of abuse (APA, 2000). 2008 (SAMHSA, 2006; SAMHSA, 2009).
Substance use disorders (SUDs) includes
both substance dependence and substance Despite the potential benefits of drug testing
abuse (APA, 2000). Substance dependence (such as monitoring pain medication) to
refers to “a cluster of cognitive, behavioral, patient care, few primary care practitioners
and physiological symptoms indicating that use it. For example, a small study conducted
the individual continues use of the substance on the medical management of patients with
despite significant substance-related chronic pain in family practices found that
problems. There is a pattern of repeated self- only 8 percent of physicians surveyed used
administration that can result in tolerance, drug testing (Adams et al., 2001).
withdrawal, and compulsive drug-taking
behavior” (APA, 2000). Substance abuse
refers to “a maladaptive pattern of substance Development of Drug Testing
use manifested by recurrent and significant
adverse consequences related to the repeated Drug testing performed for clinical reasons
use of substances” (APA, 2000). In this TAP, differs substantially from workplace drug
the term substance abuse is sometimes used testing programs. However, clinical drug
to denote both substance abuse and substance testing draws on the experience of Federal
dependence as they are defined in the DSM- Mandatory Workplace Drug Testing and,
IV-TR (APA, 2000). to understand drug testing, a review of
workplace drug testing may be helpful. An
SUDs can have serious medical complications important reason for clinical practitioners
and serious psychosocial consequences and to become familiar with Federal Mandatory
can be fatal. Treatment of other medical Workplace Drug Testing is that the majority
disorders (e.g., HIV/AIDs, pancreatitis, of drug testing is done for workplace
hypertension, diabetes, liver disorders) may purposes. For this reason, most laboratories
be complicated by the presence of an SUD. and many point-of-care tests (POCTs) use
As the front line in health care, medical the cutoff concentrations established by the
practitioners are ideally situated to identify Mandatory Guidelines for Federal Workplace
substance use problems. The 2009 National Drug Testing Programs, discussed in Chapter 2.
Survey on Drug Use and Health (Substance
Abuse and Mental Health Services There are three categories of drug testing:
Administration [SAMHSA], 2010a) found that (1) federally regulated for selected Federal
23.5 million (9.3 percent) persons ages 12 or employees (including military personnel
older needed treatment for an illicit drug1 and those in safety-sensitive positions);
or alcohol use problem. Of this population, (2) federally regulated for non-Federal
only 2.6 million (1.0 percent) persons ages employees in safety-sensitive positions (i.e.,
12 or older (11.2 percent of those who needed airline and railroad personnel, commercial
treatment) received treatment at a specialty truckers, school bus drivers); and (3)
facility. Thus, 20.9 million (8.3 percent) of the nonregulated for non-Federal employees.
population age 12 or older needed substance Commercial truck drivers, railroad employees
abuse treatment but did not receive it in the and airline personnel make up the largest
past year (SAMHSA, 2010a). Therefore, a group of individuals being drug tested.
visit to a primary care practitioner may be
an excellent opportunity for such people to be The purpose of both Federal (always
regulated) and non-Federal (may be
1
Includes the nonmedical use of prescription-type nonregulated) workplace drug testing is to
pain relievers, tranquilizers, stimulants, and sedatives. ensure safety in the workplace by preventing
3Clinical Drug Testing in Primary Care
the hiring of individuals who use illicit drugs metabolites (SAMHSA, 2008):
and identifying employees who use illicit
drugs. • Amphetamines (amphetamine,
methamphetamine)
• Cocaine metabolites
Workplace Drug Testing
• Marijuana metabolites
Drug-testing methods have been available
for approximately 50 years (Reynolds, 2005). • Opiate metabolites (codeine, morphine)
Because of drug use in the U.S. military, by • Phencyclidine (PCP)
1984, the military established standards for
laboratories and testing methods and created These substances are generally called the
the first system for processing large numbers “Federal 5,” but over the years they have also
of drug tests under strict forensic conditions been called the “NIDA 5” and “SAMHSA 5.”
that could be defended in a court of law. The Federal mandatory guidelines have been
updated and revised over the years to reflect
In 1986, an Executive Order initiated the technological and process changes (Exhibit
Federal Drug-Free Workplace Program that 1-1). The guidelines, last updated in 2008
defined responsibilities for establishing a (effective May 1, 2010), are available at http://
plan to achieve drug-free workplaces. In dwp.samhsa.gov/DrugTesting/Level_1_Pages/
1987, Public Law 100-71 outlined provisions mandatory_guidelines5_1_10.html.
for drug testing programs in the Federal
sector. In 1988, Federal mandatory guidelines Revisions for testing of other matrixes (e.g.,
set scientific and technical standards for hair, oral fluid, sweat) and the use of POCTs
testing Federal employees. In 1989, the U.S. were proposed in 2004 (SAMHSA, 2008), but
Department of Transportation (DOT) issued have not been finalized.
regulations requiring the testing of nearly 7
million private-sector transportation workers Although Federal agencies are required
in industries regulated by DOT. to have drug-free workplace programs for
their employees, private-sector employers
The Federal mandatory guidelines included that do not fall under Federal regulations
procedures, regulations, and certification can establish their own drug-free workplace
requirements for laboratories; outlined the programs and establish their own
drugs for which testing was to be performed; regulations, testing matrices, and testing
set cutoff concentrations; and stated reporting methods. Non-Federal employees can be
requirements that included mandatory medical tested for a broader range of drugs than the
reviews by a specially trained physician federally mandated drugs. Many States have
Medical Review Officer (MRO). Because a laws and regulations that affect when, where,
positive result does not automatically identify and how employers can implement drug-free
an employee or job applicant as a person workplace programs (search in http://www.
who uses illicit drugs, the MRO interviews dol.gov).
the donor to determine whether there is an
alternative medical explanation for the drug Laboratories are accredited by the National
found in the specimen. The Federal mandatory Laboratory Certification Program (NLCP)
guidelines recommended that the initial to meet the minimum requirements of the
screening test identify the presence of the Federal mandatory guidelines. This program
following commonly abused drugs or their resides in SAMHSA in the Department of
Health and Human Services (HHS).
4Chapter 1―Introduction
Exhibit 1-1. U.S. Department of Health and Human Services Federal Mandatory Workplace
Guidelines Cutoff Concentrations for Initial and Confirmatory Drug Tests in Urine
Federal Cutoff
Initial Test Analyte Concentrations (ng/mL)
Marijuana metabolites 50
Cocaine metabolites 150
Opiate metabolites (codeine/morphine ) 1
2,000
6-Acetylmorphine (6-AM) 10
Amphetamines (Amphetamine /methamphetamine)
2
500
Phencyclidine (PCP) 25
Methylenedioxymethamphetamine (MDMA) 500
Federal Cutoff
Confirmatory Test Analyte
Concentrations (ng/mL)
Amphetamine 250
Methamphetamine3 250
MDMA 250
Methylenedioxyamphetamine (MDA) 250
Methylenedioxyethylamphetamine (MDEA) 250
Cannabinoid metabolite (delta-9-tetrahydrocannabinol-9-carboxylic acid) 15
Cocaine metabolite (benzoylecgonine) 100
Codeine 2,000
Morphine 2000
6-Acetylmorphine (6-AM) 10
PCP 25
Source: SAMHSA (2008).
1
Morphine is the target analyte for codeine/morphine testing.
2
Methamphetamine is the target analyte for amphetamine/methamphetamine testing.
3
To be reported positive for methamphetamine, a specimen must also contain amphetamine at a concentration equal to, or greater
than, 100 ng/mL.
Drug Testing in Substance Abuse testing for drug treatment programs under
Treatment and Healthcare Settings Federal mandates.
Substance abuse treatment programs Drug testing in SUD treatment is:
use drug testing extensively. Drug
testing for patient monitoring in SUD • Part of the initial assessment of a patient
treatment programs began considerably being evaluated for a diagnosis of an SUD;
before workplace drug testing and has
• A screen to prevent potential adverse
become an integral part of many drug
effects of pharmacotherapy (e.g., opioid
treatment programs for patient evaluation
screen prior to starting naltrexone);
and monitoring. By 1970, the Federal
Government implemented specific mandatory • A component of the treatment plan for an
testing requirements for treatment programs SUD;
that were licensed by the U.S. Food and
• A way to monitor the patient’s use
Drug Administration to dispense methadone
of illicit substances or adherence to
or that received Federal funds. During the
pharmacotherapy treatment for SUDs; and
1970s, Federal agencies developed a program
to monitor laboratories performing drug • A way to assess the efficacy of the
treatment plan (i.e., level of care).
5Clinical Drug Testing in Primary Care
Drug testing can also be used to document drug testing in clinical settings (Exhibit 1-2).
abstinence for legal matters, disability Despite the differences, Federal workplace
determinations, custody disputes, or drug-testing guidelines and cutoff
reinstatement in certain professions (e.g., concentrations continue to influence clinical
lawyers, healthcare providers, airline pilots). drug testing. For example, many laboratories
and POCT devices test either for the federally
Drug testing is also useful in healthcare mandated drugs or for the same drugs, but
settings: using modified cutoff concentrations as the
default drug-testing panel. These panels are
• For determining or refuting perinatal not suitable for clinical drug testing because
maternal drug use; these panels do not detect some of the most
• As an adjunct to psychiatric care and commonly prescribed pain medications, such
counseling; as synthetic opioids (e.g., hydrocodone) and
anxiolytics (e.g., benzodiazepines, such as
• For monitoring medication compliance alprazolam), or other drugs of abuse. Initial
during pain treatment with opioids; screening test cutoffs may not be low enough
for clinical practice in some instances (e.g.,
• For monitoring other medications that
cannabinoids, opiates, amphetamines).
could be abused or diverted; and
• To detect drug use or abuse where it may
have a negative impact on patient care in Caution
other medical specialties.
Trends in drug use and abuse change over
See Chapter 4 for more information about the time and can necessitate a change in drug
use of drug testing in clinical situations. testing panels. The technology for drug
testing evolves quickly, new drug-testing
devices become available, and old tests are
Differences Between Federal refined. Although this TAP presents current
Workplace Drug Testing and information, readers are encouraged to
continue to consult recent sources. Wherever
Clinical Drug Testing possible, the TAP refers readers to resources
Important distinctions exist between drug that provide up-to-date information.
testing in Federal workplace settings and
6Chapter 1―Introduction
Exhibit 1-2. Comparison of Federal Workplace Drug Testing and Clinical Drug Testing
Component Federal Workplace Testing Clinical Testing
Specimen • Urine • Primarily urine, some oral fluid tests
Collection • Federal regulations stipulate specimen • Practitioners and clinical staff (hospital or clinical
Procedures collection procedures. laboratory) follow procedures for properly
• Policies minimize mistaken identity of identifying and tracking specimens.
specimens and specimen adulteration. • In general, rigorous protocols are not used.
For example, in criminal cases, Chain of custody usually is not required;
chain-of-custody policies require however, laboratories under College of American
identification of all persons handling Pathologists accreditation and/or State licensure
specimen packages. In administrative should have specimen collection, handling, and
cases (e.g., workplace testing), specimen storage protocols in place.
packages may be handled without
individual identification. Only those persons
handling the specimen itself need to be
identified.
Specimen • Extensive testing verifies that specimen • In general, laboratories do not conduct the
Validity Testing substitution or adulteration has not same validity testing as is required for Federal
occurred. workplace testing.
• Validation often is not required with clinical use
of POCT.
• Some laboratories record the temperature of
the specimen and test for creatinine and specific
gravity of urine specimens.
• Pain management laboratories may have
specimen validity testing protocols that involve
creatinine with reflexive specific gravity, pH,
and/or oxidants in place.
Confirmatory • Gas chromatography/mass spectrometry • GC/MS, liquid chromatography/mass
Methods (GC/MS) spectrometry (LC/MS), liquid chromatography/
mass spectrometry/mass spectrometry LC/MS/
MS.
Testing for • Testing is for the federally mandated drugs. • No set drug testing panel.
Predetermined • Drugs tested vary by laboratory and within
Substances laboratories.
• Clinicians may specify which drugs are tested for
and usually select panels (menus) that test for
more than the federally mandated drugs. Various
panels exist (e.g., pain).
Cutoff • Cutoff concentrations have been • Cutoff concentrations vary.
Concentrations established for each drug. • In some circumstances, test results below the
• A test detecting a concentration at or cutoff concentration may be clinically significant.
above the cutoff is considered to be a • Urine and oral fluid drug concentrations are
positive result; a test detecting nothing, usually not well correlated with impairment
or a concentration below the cutoff, is or intoxication, but may be consistent with
considered to be a negative result. observed effects.
Laboratory • Testing must be conducted at an HHS, • Laboratories do not need HHS certification.
Certification SAMHSA-certified laboratory. However, clinical laboratories in the United
States and its territories must be registered with
Clinical Laboratory Improvement Amendments
(CLIA) and comply with all State and local
regulations concerning specimen collection,
clinical laboratory testing, and reporting.
• POCT using kits calibrated and validated
by manufacturers does not require CLIA
certification.
Medical Review • A physician trained as an MRO must • MRO review is not required.
interpret and report results.
7Chapter 2—Terminology and Essential
Concepts in Drug Testing
Drug Screening and Confirmatory Testing
In This Chapter
Traditionally, drug testing usually, but not always, involves
• Drug Screening and a two-step process: an initial drug screen that identifies
Confirmatory Testing potentially or presumptively positive and negative specimens,
• Testing Methods followed by a confirmatory test of any screened positive
assays.
• Test Reliability
• Window of Detection Screening tests (the initial tests) indicate the presence
or absence of a substance or its metabolite, but also can
• Cutoff Concentrations indicate the presence of a cross-reacting, chemically similar
substance. These are qualitative analyses—the drug (or drug
• Cross-Reactivity
metabolite) is either present or absent. The tests generally
• Drug Test Panels do not measure the quantity of the drug or alcohol or its
metabolite present in the specimen (a quantitative analysis).
• Test Matrix Screening tests can be done in a laboratory or onsite
• Point-of-Care Tests (point-of-care test [POCT]) and usually use an immunoassay
technique. Laboratory immunoassay screening tests are
• Adulterants inexpensive, are easily automated, and produce results
• Specimen Validity quickly. Screening POCT immunoassay testing devices are
Tests available for urine and oral fluids (saliva). Most screening
tests use antigen–antibody interactions (using enzymes,
microparticles, or fluorescent compounds as markers) to
compare the specimen with a calibrated quantity of the
substance being tested for (Center for Substance Abuse
Treatment, 2006b).
Confirmatory tests either verify or refute the result of the
screening assay. With recent improvements in confirmation
technology, some laboratories may bypass screening tests
and submit all specimens for analysis by confirmatory
tests. It is the second analytical procedure performed on
a different aliquot, or on part, of the original specimen to
identify and quantify the presence of a specific drug or drug
metabolite (Substance Abuse and Mental Health Services
Administration [SAMHSA], 2008). Confirmatory tests use
a more specific, and usually more sensitive, method than do
screening tests and are usually performed in a laboratory.
Confirmatory tests usually:
• Provide quantitative concentrations (e.g., ng/mL) of specific
substances or their metabolites in the specimen.
• Have high specificity and sensitivity.
9Clinical Drug Testing in Primary Care
• Require a trained technician to perform Testing Methods
the test and interpret the results.
Conventional scientific techniques are
• Can identify specific drugs within drug used to test specimens for drugs or drug
classes. metabolites. Most commonly, immunoassay
testing technology is used to perform the
In clinical situations, confirmation is not
initial screening test (Meeker, Mount, &
always necessary. Clinical correlation is
Ross, 2003). Appendix B, Laboratory Initial
appropriate. For example, if the patient
Drug-Testing Methods, briefly describes these
or a family member affirms that drug use
methods.
occurred, a confirmation drug test is not
usually needed. The most common technologies used to
perform the confirmatory test are gas
A POCT, performed where the specimen is
chromatography/mass spectrometry, liquid
collected, is a screening test. A confirmatory
chromatography/mass spectrometry, and
drug test is usually more technically complex
various forms of tandem mass spectrometry.
and provides definitive information about
Information about these methods and other
the quantitative concentrations (e.g., ng/mL)
confirmatory testing methods are in Appendix
of specific drugs or their metabolites in the
C, Laboratory Confirmatory Drug-Testing
specimen tested. However, the term drug
Methods. Other testing methods are used to
screening or testing is misleading in that it
detect adulteration or substitution. Appendix
implies that all drugs will be identified by
D, Laboratory Specimen Validity-Testing
tests, whereas the drug or drug metabolites
Methods, provides a short explanation of
detected by a test depend on the testing
methods for specimen validity testing.
method and the cutoff concentration.
In Federal workplace testing, all positive
initial screening test results must be followed Test Reliability
by a confirmatory test (SAMHSA, 2008). Both POCTs and laboratory tests are
In clinical settings, however, confirmatory evaluated for reliability. Two measures
testing is at the practitioner’s discretion. of test reliability are sensitivity and
Laboratories do not automatically perform specificity, which are statistical measures
confirmatory tests. When a patient’s of the performance of a test. The sensitivity
screening test (either a POCT or laboratory indicates the proportion of positive results
test) yields unexpected results (positive that a testing method or device correctly
when in substance use disorder (SUD) identifies. For drug testing, it is the test’s
treatment, or negative if in pain management ability to reliably detect the presence of a
treatment), the practitioner decides whether drug or metabolite at or above the designated
to request a confirmatory test. In addition, cutoff concentration (the true-positive
a confirmatory test may not be needed; rate). Specificity is the test’s ability to
patients may admit to drug use or not taking exclude substances other than the analyte
scheduled medications when told of the of interest or its ability not to detect the
drug test results, negating the necessity analyte of interest when it is below the cutoff
of a confirmatory test. However, if the concentration (the true-negative rate). It
patient disputes the unexpected findings, a indicates the proportion of negative results
confirmatory test should be done. Chapter 4 that a testing method or device correctly
provides information that can be helpful in identifies.
deciding whether to request a confirmatory
test.
10Chapter 2—Terminology and Essential Concepts in Drug Testing
Tests are designed to detect whether a Window of Detection
specimen is positive or negative for the
substance. Four results are possible: The window of detection, also called the
detection time, is the length of time the
• True positive: The test correctly detects the substances or their metabolites can be
presence of the drug or metabolites. detected in a biological matrix. It part, it
depends on:
• False positive: The test incorrectly detects
the presence of the drug when none is • Chemical properties of the substances for
present. which the test is being performed;
• True negative: The test correctly confirms • Individual metabolism rates and excretion
the absence of the drug or metabolites. routes;
• False negative: The test fails to detect the • Route of administration, frequency of use,
presence of the drug or metabolites. and amount of the substance ingested;
Confirmatory tests must have high • Sensitivity and specificity of the test;
specificity. Generally, screening tests have
relatively low specificity. Screening tests are • Selected cutoff concentration;
manufactured to be as sensitive as possible, • The individual’s health, diet, weight,
while minimizing the possibility of a false- gender, fluid intake, and pharmacogenomic
positive result (Dolan, Rouen, & Kimber, profile; and
2004). Notable exceptions from common
manufacturers of laboratory-based or point- • The biological specimen tested.
of-care immunoassay kits are cannabinoids, All biological matrices may show the presence
cocaine metabolite, oxycodone/oxymorphone, of both parent drugs and their metabolites
methadone, and methadone metabolite (Warner, 2003). Drug metabolites usually
(EDDP, or 2-ethylidine-1,5-dimethyl-3,3 remain in the body longer than do the parent
diphenylpyrrolidine). Other examples may drugs. Blood and oral fluid are better suited
exist. With the exceptions noted previously, for detecting the parent drug; urine is most
they cannot reliably exclude substances other likely to contain the drug’s metabolites.
than the substance of interest (the analyte), Exhibit 2-1 provides a comparison of
and they cannot reliably discriminate among detection periods used for various matrices.
drugs of the same class. For example, a low-
specificity test may reliably detect morphine, Many factors influence the window of
but be unable to determine whether the drug detection for a substance. Factors include,
used was heroin, codeine, or morphine. but are not limited to, the frequency of drug
use (chronic or acute), the amount taken, the
Generally, the cutoff level for initial screening rate at which the substance is metabolized
tests is set to identify 95–98 percent of (including pharmacogenomic abnormalities,
true-negative results, and 100 percent of such as mutations of CYP2D6 and other
true-positive results. Confirmatory test drug-metabolizing enzymes [White & Black,
cutoff concentrations are set to ensure that 2007]), the cutoff concentration of the test,
more than 95 percent of all specimens with the patient’s physical condition and, in many
screened positive results are confirmed as cases, the amount of body fat.
true positives (Reynolds, 2005). However,
confirmation rates are highly dependent upon
the analyte. For cannabinoids and cocaine
metabolite, the confirmatory rate usually
exceeds 99 percent. The clinically important
point is that false positives are rare for
cocaine metabolite or cannabinoids.
11Clinical Drug Testing in Primary Care
Exhibit 2-1. Window of Detection for Various Matrices
Matrix Time*
Breath
Blood
Oral Fluid
Urine
Sweat†
Hair‡
Meconium
Minutes Hours Days Weeks Months Years
*Very broad estimates that also depend on the substance, the amount and frequency of the substance taken, and other factors
previously listed.
†As long as the patch is worn, usually 7 days.
‡7–10 days after use to the time passed to grow the length of hair, but may be limited to 6 months hair growth. However, most
laboratories analyze the amount of hair equivalent to 3 months of growth.
Sources: Adapted from Cone (1997); Dasgupta (2008).
Cutoff Concentrations Detection thresholds for Federal, employer,
and forensic drug testing panels are set high
The administrative cutoff (or threshold) of a enough to detect concentrations suggesting
drug test is the point of measurement at or drug abuse, but they do not always detect
above which a result is considered positive therapeutic concentrations of medications.
and below which a result is considered For example, the threshold for opiates in
negative. This level is established on the federally mandated workplace urine drug
basis of the reliability and accuracy of screening is 2000 ng/mL. The usual screening
the test and its ability to detect a drug or threshold for opiates in clinical monitoring
metabolite for a reasonable period after drug is much lower, at 300 ng/mL for morphine,
use (see Test Reliability). hydrocodone, and codeine (Christo et al.,
2011) to detect appropriate use of opioid pain
Before the establishment of the Federal medication.
mandatory guidelines, cutoff concentrations
for screening tests were determined by the For laboratory tests, practitioners can
manufacturer of the test or the laboratory. request lower cutoff concentrations than
Because the majority of drug testing is done are commonly used in workplace testing.
for workplace purposes, most laboratories However, in some cases, the error rate
and many POCTs use the Federal mandatory increases as the cutoff concentration
guidelines for workplace testing cutoff decreases.
concentrations. However, Federal cutoff
concentrations are not appropriate for
clinical use. Practitioners need to know the
cutoff concentrations used in the POCTs,
Cross-Reactivity
or by the laboratory testing their patients’ Cross-reactivity occurs when a test cannot
specimens, and should understand which distinguish between the substances being
analyte and at what cutoff the test is tested for and substances that are chemically
designed to detect. similar. This is a very important concept
when interpreting test results.
12Chapter 2—Terminology and Essential Concepts in Drug Testing
Drug class-specific immunoassay tests Practitioners can find some of this
compare the structural similarity of a information in the instructions in the POCT
drug or its metabolites with specially packaging material, or they can talk with
engineered antibodies. The ability to detect laboratory personnel to know exactly what a
the presence of a specific drug varies with laboratory’s tests will and will not detect.
different immunoassay tests, depending
on the cross-reactivity of the drug with an
antibody. For example, a test for opioids may Drug Test Panels
be very sensitive to natural opioids, such
as morphine, but may not cross-react with A drug test panel is a list (or menu) of drugs
synthetic or semisynthetic opioids, such as or drug classes that can be tested for in a
oxycodone. specimen. These can be ordered to identify
drugs of abuse or in pain management.
Substances other than the drug to be detected No single drug panel is suitable for all
may also cross-react with the antibody clinical uses; many testing options exist
and produce a false-positive result. Some that can be adapted to clinical needs. These
over-the-counter (OTC) decongestants (e.g., panels are designed to monitor adherence
pseudoephedrine) register a positive drug to pain treatment plans, to detect use
test result for amphetamine. Phentermine, of nonprescribed pain medications, and
an anorectic agent, commonly yields a to screen for use of illicit drugs. Clinical
false-positive initial amphetamines test. practitioners can order more comprehensive
Dextromethorphan can produce false-positive drug test panels to identify drugs or classes of
results for phencyclidine (PCP) in some assays. drugs that go beyond the federally mandated
Cross-reactivity can be beneficial in clinical drugs for testing. Which drugs are included
testing. As an example, a urine test that in the testing menu vary greatly between
is specific for morphine will detect only and within laboratories; laboratories differ
morphine in a patient’s urine. The morphine- in the drugs or metabolites included in their
specific test will miss opioids, such as comprehensive panel and have more than
hydrocodone and hydromorphone. A urine one type of panel. Therefore, practitioners
drug test or panel that is reactive to a wide should contact their laboratory to determine
variety of opioids would be a better choice for the capabilities and usual practices of the
a clinician when looking for opioid use by a laboratory. It is just as important for a
patient. Conversely, the lack of sensitivity to clinical practitioner to know what a “urine
the common semisynthetic opioid, oxycodone, drug screen” will not detect as it is to know
is detrimental to patient care when a what it will detect. Some laboratories have
clinician is reviewing the results of a “urine a comprehensive pain management panel
drug screen” and sees “opiates negative” for people prescribed opioids for pain (Cone,
when oxycodone abuse is suspected. Thus, Caplan, Black, Robert, & Moser, 2008).
cross-reactivity can be a double-edged sword Panels can be customized for individual
in clinical practice. practices or patients, but using existing
test panels from the laboratory is generally
To avoid false-positive results caused by less expensive for patients and less time-
cross-reactivity, practitioners should be consuming for practitioners than ordering
familiar with the potential for cross-reactivity tests for many individual substances.
and ask patients about prescription and OTC However, these panels vary by laboratory
medication use. and are not standardized. However, it
should be noted that laboratories may default
Drug-testing accuracy continues to improve. to the federally mandated drug tests if a
For example, newer drug tests may correct practitioner does not order a different test
for interactions that have been formerly panel.
associated with false-positive results.
13Clinical Drug Testing in Primary Care
Panels are available in various configurations. has a different window of detection. Urine
The more drugs on a panel, the more is the most widely used test matrix (Watson
expensive the test. Substances typically on et al., 2006). Detailed information about test
these panels include, but are not limited to: matrices is in Chapter 3.
• Amphetamine, methamphetamine.
• Barbiturates (amobarbital, butabarbital, Point-of-Care Tests
butalbital, pentobarbital, phenobarbital, A POCT is conducted where the specimen is
secobarbital). collected, such as in the practitioner’s office.
• Benzodiazepines (alprazolam, POCTs use well-established immunoassay
chlordiazepoxide, clonazepam, clorazepate, technologies for drug detection (Watson et al.,
diazepam, flurazepam, lorazepam, 2006).
oxazepam, temazepam).
POCTs:
• Illicit drugs (cocaine,
methylenedioxyamphetamine [MDA], • Reveal results quickly;
methylenedioxymethamphetamine [MDMA],
methylenedioxyethylamphetamine [MDEA], • Are relatively inexpensive ($5–$20,
marijuana). depending on the POCT, the drugs or drug
metabolites tested for, and the number of
• Opiates/opioids (codeine, dihydrocodeine, tests purchased);
fentanyl, hydrocodone, hydromorphone,
meperedine, methadone, morphine, • Are relatively simple to perform; and
oxycodone, oxymorphone, propoxyphene). • Are usually limited to indicating only
positive or negative results (qualitative,
The practitioner should consult with the
not quantitative).
laboratory when determining the preferred
test panels. When reading the test results, it is important
to know that how quickly the test becomes
The test menu for POCTs differs per positive or the depth of the color do not
the manufacturer and the device. Most indicate quantitative results.
POCTs screen for drugs included in the
federally mandated test panel and other A comparison of POCTs and laboratory tests
drugs or metabolites. Different devices and is in Chapter 3.
manufacturers offer various configurations of
drugs tested for in devices.
Adulterants
Test Matrix An adulterant is a substance patients can
add to a specimen to mask the presence of
A test matrix is the biological specimen used a drug or drug metabolite in the specimen,
for testing for the presence of drugs or drug creating an incorrect result to hide their drug
metabolites. Almost any biological specimen use. Methods to detect adulterants exist, and
can be tested for drugs or metabolites, but most laboratories and some POCTs can detect
the more common matrices include breath common adulterants. No one adulterant
(alcohol), blood (plasma, serum), urine, sweat, (with the exception of strong acids, bases,
oral fluid, hair, and meconium. Depending oxidizers, and reducing agents) can mask
on its biological properties, each matrix the presence of all drugs. The effectiveness
can provide different information about a of an adulterant depends on the amount of
patient’s drug use. For example, the ratio the adulterant and the concentration of the
of parent drug to metabolite in each matrix drug in the specimen. A specimen validity
can be decidedly different, and each matrix
14Chapter 2—Terminology and Essential Concepts in Drug Testing
test can detect many adulterants. Numerous Additional information on validity follows:
adulterants are available, especially for urine
(see Chapter 5). • The pH for normal urine fluctuates
throughout the day, but usually ranges
between approximately 4.5 and 9.0.
Specimen Validity Tests Specimens outside this range are usually
reported by the laboratory as invalid.
Specimen validity tests determine whether a Specimen adulteration should be suspected
urine specimen has been diluted, adulterated, if the pH level is less than 3.0 or greater
or substituted to obtain a negative result. than 11.0.
A specimen validity test can compare urine
specimen characteristics with acceptable • Creatinine is a normal constituent in urine
density and composition ranges for human at concentrations greater than or equal to
urine, detect many adulterants (e.g., 20 mg/dL. If the creatinine is less than 20
oxidizing compounds), or test for a specific mg/dL, the specimen is tested for specific
compound (e.g., nitrite, chromium VI) at gravity.
concentrations indicative of adulteration. • Specific gravity of urine is a measure of
Many laboratories perform creatinine and the concentration of particles in the urine.
pH analyses of all specimens submitted for Only specimens whose creatinine is less
drug testing. An adulteration panel can be than 20 mg/dL need to be reflexively
ordered that determines the characteristics tested for specific gravity, although
of the urine sample (e.g., creatinine level specific gravity may be an integral part of
with reflexive specific gravity when a low a POCT device’s specific validity testing
creatinine is encountered) and checks for panel. Specimens with a low creatinine
the presence of common adulterants. POCT and an abnormal specific gravity may be
devices are available that test for specimen reported as dilute, invalid, or substituted,
validity, as well. depending on the laboratory’s reporting
policies (SAMHSA, 2008).
Although validity testing is not required in
clinical settings, it is sometimes advisable if If the laboratory finds the specimen is
the patient denies drug use. For example, a dilute, it will report the specimen as dilute.
physician treating a patient for an SUD may However, the laboratory will also report the
want to request validity testing if the patient positive or negative test results. Depending
exhibits signs of relapse, but has negative on the degree of dilution, an analyte may still
test results. Point-of-care validity tests are be detected.
available, and some POCT devices also test
for validity at the same time they test for the Appendix D provides more information on
drug analyte. laboratory specimen validity tests.
15Chapter 3—Preparing for Drug Testing
Deciding Which Drugs To Screen and Test For
In This Chapter
When using drug tests to screen a patient for substance use
• Deciding Which Drugs disorders, the practitioner should test for a broad range of
To Screen and Test drugs. Decisions about which substances to screen for can be
For based on:
• Choosing a Matrix
• The patient, including history, physical examination, and
• Selecting the laboratory findings;
Initial Testing
Site: Laboratory or • The substance suspected of being used;
Point-of-Care • The substances used locally (the Substance Abuse and
• Preparing a Specimen Mental Health Services Administration’s [SAMHSA’s]
Collection Site Drug Abuse Warning Network compiles prevalence data
on drug-related emergency department visits and deaths;
information is available at http://www.samhsa.gov/data/
DAWN.aspx);
• The substances commonly abused in the practitioners’
patient population; and
• Substances that may present high risk for additive or
synergistic interactions with prescribed medication (e.g.,
benzodiazepines, alcohol).
Choosing a Matrix
Practitioners can choose among several matrices for drug
and alcohol testing for adults: urine, oral fluid, sweat, blood,
hair, and breath (alcohol only). Neonates can be tested using
meconium. Urine is the most commonly used matrix for drug
testing and has been the most rigorously evaluated (Watson
et al., 2006); it is discussed at length in Chapter 5. Exhibit
3-1 provides a brief comparison of the advantages and
disadvantages of the seven matrices.
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