Fundamentals of Analytical Toxicology

Clinical and Forensic

Robert J. Flanagan, Eva Cuypers, Hans H. Maurer, Robin Whelpton

• Publisher: Wiley
• Year: 2020
• Print ISBN: 9781119122340
• eBook ISBN: 9781119122371
• Edition: 2
• Topic: Physical Sciences
• Subtopic: Chemistry
• Index: Chemistry

Fundamentals of Analytical Toxicology is an integrated introduction to the analysis of drugs, poisons, and other foreign compounds in biological and related specimens. Assuming only basic knowledge of analytical chemistry, this invaluable guide helps trainee analytical toxicologists understand the principles and practical skills involved in detecting, identifying, and measuring a broad range of compounds in various biological samples. Clear, easy-to-read chapters provide detailed information on topics including sample collection and preparation, spectrophotometric and luminescence techniques, liquid and gas-liquid chromatography, and mass spectrometry including hyphenated techniques.

This new edition contains thoroughly revised content that reflects contemporary practices and advances in analytical methods. Expanding the scope of the 1995 World Health Organization (WHO) basic analytical toxicology manual, the text includes coverage of separation science, essential pharmacokinetics, xenobiotic absorption, distribution and metabolism, clinical toxicological and substance misuse testing, therapeutic drug monitoring, trace elements and toxic metals analysis, and importantly the clinical interpretation of analytical results.

Written by a prominent team of experienced practitioners, this volume:

• Focuses on analytical, statistical, and pharmacokinetic principles
• Describes basic methodology, including colour tests and immunoassay and enzyme-based assays
• Outlines laboratory operations, such as method validation, quality assessment, staff training, and laboratory accreditation
• Follows IUPAC nomenclature for chemical names and recommended International Non-proprietary Name (rINN) for drugs and pesticides
• Includes discussion of 'designer drugs' (novel pharmaceutical substances NPS)

Fundamentals of Analytical Toxicology: Clinical and Forensic, 2^nd Edition is an indispensable resource for advanced students and trainee analytical toxicologists across disciplines, such as clinical science, analytical chemistry, forensic science, pathology, applied biology, food safety, and pharmaceutical and pesticide development.

Section D
Analytical Toxicology

17
Toxicology Testing at the Point of Contact

17.1 Introduction

Point of contact testing (point of care testing, POCT), as its name implies, refers to testing carried out in close proximity to the subject, usually with the aim of providing an almost immediate result. It can be considered as any testing performed outside of a central laboratory and may also be referred to as point of care laboratory testing (POCLT), rapid oral fluid testing (ROFT), bedside testing, near patient testing (NPT), home testing, and patient self-management (Table 17.1).

Table 17.1 Examples of point of contact testing

Type of Monitoring	Analyte	Test sample
Emergency department, trauma clinic	Blood gases, carbon monoxide, ethanol, paracetamol, salicylates, substance misuse, snake envenomation	Blood, urine, oral fluid, breath
Therapeutic monitoring	Lithium, theophylline	Blood, plasma
Roadside testing	Cannabis, cocaine, ethanol	Breath, oral fluid
Workplace testing
Pre-employment	Substance misuse	Urine, oral fluid
On-site	Ethanol, substance misuse	Breath, oral fluid, sweat
Detention centres	Substance misuse	Urine, oral fluid, sweat
Drug treatment clinics	Buprenorphine, ethanol, methadone, substance misuse	Urine, oral fluid, sweat
Self-management	Warfarin	Blood

With the use of POCT systems for testing for driving under the influence (DUI) of drugs (including ethanol) or screening for possible impairment in the workplace, roadside, and employment and pre-employment testing can be added to the list. Consideration of issues such as staff training, QA, and the interpretation of results are inherent in any decision to implement testing (Shephard, 2016; Nichols & Petersmann, 2019).

17.2 Use of point of contact testing

The use of a POCT system should be given careful consideration before such a programme is initiated (Box 17.1). POCT may be performed to aid diagnosis of disease, guide therapy, or detect poisons. However, in the context of analytical toxicology the term is more generally applied to screening for, or assessing the concentration of, illicit or otherwise proscribed substances.

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Box 17.1 Questions when deciding to implement point of contact testing

• What are the reasons for testing?
  1. – Emergency department testing/drug treatment clinic
  2. – Law enforcement
  3. – Post-incident
  4. – Random or scheduled workplace testing/pre-employment screening
• Why are immediate results required?
  1. – Initiate early treatment/alter treatment
  2. – Effect an arrest
  3. – Suspend from work
• What is the window of detection to be?
  1. – May influence choice of fluid to be sampled
  2. – Currently under the influence
  3. – Detect a regular substance misuser
• Which drugs should be detected?
  1. – Ethanol
  2. – Misused drugs
• Where are the tests to be done?
  1. – Clinic
  2. – Roadside
  3. – Workplace
• What tests are available?
  1. – Are the kits suitable for the task/venue?
  2. – Will the operators be able to use the system correctly?
  3. – Is storage/shelf-life a consideration?
• Will it be cost effective?
  1. – Avoid need to transport samples to the laboratory for analysis
  2. – Avoid need for employee to visit the test laboratory
  3. – Reduce the number of samples to be assayed by the laboratory – only test putative positives
  4. – Cost of kits/numbers of samples

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The nature of the tests performed will depend on where they are being carried out. An emergency department will have access to blood gas analyzers, and these may be able to perform COHb assay. On the other hand, roadside or point-of-entry testing kits for use by trained police or customs officials need to be portable, robust, and reliable, whilst POCT kits for workplace testing need t...

Table of contents

• Cover
• Table of Contents
• Preface
• Health and Safety
• Nomenclature, Symbols, and Conventions
• Uniform Resource Locators
• Amount Concentration and Mass Concentration
• Acknowledgements
• List of Abbreviations
• Section A: The Basics
• Section B: Separation Science
• Section C: Essential Pharmacokinetics
• Section D: Analytical Toxicology
• Index
• End User License Agreement