Clinical Applications: Drugs of Abuse Testing - Fact vs. Fiction Online Training
There are many issues and numerous misconceptions regarding drug testing. This presentation addresses some of those issues and provides accurate science-based information. This online training qualifies for Continuing Education Units (CEU).
Welcome to the Drugs of Abuse Testing: Facts versus Fiction Online Training course. This course will address some of the issues and misconceptions regarding drug testing and provides accurate science-based information. Select Next to continue. Course developed by: Dr. Leo Kadehjian Upon successful completion of this course, you will be able to: Describe the use of immunoassays for the detection of drugs and their metabolites Describe the roles and capabilities of immunoassays and confirmation methods Describe how donors may attempt to thwart effective drug testing and the tools to detect such efforts Describe the interpretation of test results for various drugs Select Next to continue. Drug testing technologies: Immunoassays Confirmation Test specimens: Urine Alternative specimens Drug specific issues: Cocaine Marijuana Amphetamines Opiates Ethanol Initial testing: Immunoassay Analyzer: Objective, qualitative and quantitative Manually-read: Subjective, qualitative only Confirmation: Chromatography/Mass spectrometry GC/MS, LC/MS, LC/MS/MS … Qualitative: (positive, negative) vs. Quantitative: (ng/mL, immunoreactive equivalents, rate units) vs. “Semi-quantitative”: (no such thing!?) Assay Response Drug Concentration Cut-off "Negative" "Positive" “Negative” does NOT mean “No drug” Assay Response Drug Concentration Cut-off signal Cut-off Concentration "Positive Specimen" "Negative Specimen" Drug Free Control Users True - False + Non-Users Negative Test Negative Test Positive Test True - False + Non-Users Users True + False - Unconfirmed + The Amphetamines Assay provides only a preliminary analytical test result. A more specific alternative chemical method must be used to obtain a confirmed analytical result. Gas chromatography/mass spectrometry (GC/MS) is the preferred confirmatory method (1). Other chemical confirmation methods are available. Clinical consideration and professional judgment should be applied to any drug-of-abuse test result, particularly when preliminary positive results are used. Visually-Read Immunoassay Test Devices Benefits Issues Rapid results Drugs and validity tests Many devices, formats Good accuracy (variable) Established scientific literature (variable) Cost (?) Subjective reading Many devices, formats Urine only (oral fluid?) Tend to be “aggressive” Limited performance studies No formal regulatory scheme No formal proficiency program Limited case law 0 High Cut-off Ideal Balanced Aggressive Conservative Benefits: Established Large volume High drug concentrations Issues: Are samples infectious? Creating “false negative” results: Adulterants Dilution Urine production, mL/min Minutes E. Baldes and F. Smirk, 1934 Drink 1L. of water Drink 2 L. of water A. Macallum and C. Benson, 1909 Hours ng/mL Cut-off Dilute x8 Hours ng/mL Cut-off Dilute x8 Cannabinoids, ng/mL Hours E. Cone et al., 1998 Cut-off Without water load 12 oz. With water load Cannabinoids, ng/mL Date Cut off = 50 ng/mL Cannabinoids ng/mL mg/dL ng/mg Creatinine Cannabinoids normalized Urine Oral Fluid Sweat Hair What other specimen types can be used? “Also, scientific advances in the use of head hair, sweat, and oral fluid in detecting drugs have made it possible for these specimens to be used in Federal programs with the same level of confidence that has been applied to the use of urine.” SAMHSA, Federal Register, 4/13/04, 69 FR 19689 Detection Time (days) Hair Sweat Urine (cannabls) Urine Oral Fluid Breath Benefits: Readily accessible Less invasive Collection easily observed Detection within 1 hour Mechanism: Passive diffusion from blood (except THC) Role of pH (increases with flow rate) Concerns: Low specimen volume Low drug levels Substitution (use IgG) Contamination? (further studies needed, must also collect urine) Time, Hours THC, ng/mL (Diluted 1:2) Niedbala et al., 2001 Average, n=15 1 joint ≈ 20-25 mg THC Benefits Non-invasive Extended wear Generally accepted by patients Tampering visible Mechanism Poorly understood, passive diffusion from blood, transdermal migration Concerns External contamination (believed not possible normally) Skin contamination (wash soap/water, alcohol, further research) Skin sensitivity Stigma if visible Benefits Long detection window (~3 mo.) Easy collection / transport / storage Lower infection risk More difficult to adulterate Detect at pg levels Mechanism Passive diffusion from blood, sweat, sebum Amount proportional to blood concentration Can estimate time of use Concerns Environmental contamination (use metabolites) Hair color (racial) bias (limited studies, no significant association) Marijuana Passive inhalation Hemp foods, products Acute vs. chronic use Renewed vs. residual Synthetics Cocaine Passive inhalation Passive exposure Amphetamines Over-the-counter medications Ecstasy” (MDMA) “Bath salts” Opiates Poppy seeds Heroin, 6-Acetylmorphine Ethanol Urine ethanol Ethanol metabolites (EtG, EtS) Hours Low dose High dose @ 100 ng/mL @ 50 ng/mL GCMS @ 15 ng/ML “The Department does not believe that passive inhalation is a reasonable defense or that significant exposure can occur through passive inhalation to cause a urine specimen to be reported positive.” Substance Abuse and Mental Health Services Administration, Mandatory Guidelines for Federal Workplace Drug Testing Programs, 59 FR 29908, 6/9/94 Days after last use Normalized THC metabolite, ng/mL E. Kouri et al., 1999 Study: n = 17 Daily use for 14 years » 5000 lifetime doses THC normalized per 100 mg/dL creatinine EMIT Positive @ 20 ng/mL Results: 5/17 (29%) negative @ 1 week 9/17 (53%) negative @ 2 weeks 11/17 (65%) negative @ 3 weeks Time Cut-Off Cannabinoids With current immunoassays @ 50 ng/mL cut-off: Occasional users: positive for 1–2 days, rarely longer Documented chronic users: positive for 2–3 weeks, rarely longer Examine every positive, review intervening “negatives” Positive after 1 month ⇒ Renewed Use (conservative) 50% increase in dilution-adjusted levels ⇒ Renewed Use (conservative) Issues for consideration: Time: between test results, from claimed last use Drug levels (normalized) Pattern: levels (normalized), time, specimen ratios Specimen validity: dilution, creatinine, normalization Donor claims, history Passive inhalation Passive exposure Dose Space Time Max. BE level Reference 200 mg 4x5 ½ hr ≤15 ng/mL Baselt et al., 1991 100 mg 7x8 1 hr 22–123 ng/mL Cone et al., 1995 200 mg 7x8 1 hr 26–107 ng/mL Cone et al., 1995 87.5 mg Side stream 11x15 4 hr 0–6 ng/mL Cone et al., 1995 Cocaine Exposure Protection Max. BE (ng/mL) Open 50 x 1 kg, 3 hr Gloves 1570 @ 8 hr Gloves, mask 278 @ 24 hr Sample 9 x 1Kg, 2 Hr Gloves, mask ND Gloves, mask, goggles ND Transfer 1 kg, 25 times, ½ hr None 101 @ 12 hr Gloves, mask 39 @ 6 hr Transfer 1 kg, 50 times Gloves, mask, goggles 122 @ 48 hr Transfer 1 kg, 25 times, ½ hr Gloves, mask, goggles, cap, gown 27 @ 6 hr 82 @ 12 hr 114 @ 12 hr Le et al., 1992 Cocaine exposure Test results Reference Handle 2 x $1 bills immersed in coca paste 72 ng/mL BE El Sohly et al., 1991 Immerse hands in coca paste Just below 300 ng/mL Immerse fingers, 4% solution All EMIT negative Kavanagh et al., 1992 2 drops, 4% solution, back of hand Inhale 4% aerosol, nasal procedure . µg/mL Hours Y. Tseng et al., 2006 Pseudoephedrine (30 mg) Phenylpropanolamine (40 mg) Ephedrine (25 mg) EMIT® II Plus Cross-Reactivity @ 500 ng/mL cutoff Drug Concentration to give “positive” result Pseudoephedrine 2,600 µg/mL Phenylpropanolamine 1,000 µg/mL Ephedrine 800 µg/mL Hours M. Thevis et al., 2003 Urine morphine, ng/mL Poppy Seed Ingestion: n = 9 Morphine content: 152 µg/g poppy seeds Total morphine intake: 1.6–6.8 mg Measured codeine concentration: 60–820 ng/mL Steps to distinguish ingestion of poppy seeds from use of an opiate drug or heroin: Examine claimed consumption (positives unlikely for >1 day) Eliminate seeds from diet, collect another specimen after 3 days Test for 6-monoacetylmorphine (presence proves heroin use) Measure total morphine levels (>5000 ng/mL unlikely for seeds) Measure morphine/codeine ratio (morphine > codeine for seeds) Look for evidence of opiate use (needle tracks, needles, behavior) n “Dose” Measured Opiate Concentration 8 subjects 2 rolls 2 g. seeds all negative 7 subjects cake 14–19 g seeds 1/33 pos @ 260 ng/mL @ 5 hr 7 subjects 1–3 muffins 3–9 g seeds 22% pos, 152–730 ng/mL morphine @ 4–12 hr 9 subjects 2 bagels 3 g seeds 27% pos , 129–1456 ng/mL morphine @ 2–8 hr 4 subjects 22.5 g seeds 33% pos, 207–571 ng/mL morphine 9 subjects 2 streusels 24 g Mexican seeds all pos @ 24 hr 2 pos @ 48 hr 1 pos @ 72 hrs @ 471 ng/mL 820–11,571 ng/mL morphine trace–4861 ng/mL codeine Urine ethanol Ethanol metabolites (EtG, EtS) 95–99% metabolized 0.7% unchanged in breath 0.3% in urine 0.1 % in sweat Role of gastric alcohol dehydrogenase: ~20% of dose metabolized in stomach Women, chronic users: 50% less enzyme Average elimination rate: 0.019%/hr Chronic users: 20 – 70% increased rate Smokers: 40% increased rate Oral contraceptives: 25% decreased rate Ethanol H3C-CH2OH Alcohol dehydrogenase Aldehyde dehydrogenase Hours H. Haggard et al., 1940 Ethanol % n = 11 Dose = 250 mL whiskey @ time = 0 Urine Blood Sugar in urine and Infection and At least 1 day storage at room temperature Days (@ room temp) Helander et al., 1995 EtOH, g/dL 2 g/dL glucose 10 and 1000 cfu/mL Candida Specified by Congress in Omnibus Transportation Employee Testing Act Can reasonably accurately reflect blood levels Provides flexibility and cost savings Authorized in >1/2 of states’ implied consent laws Has withstood legal challenge as a valid specimen Ethyl Sulfate Ethyl Glucuronide Fatty acid Fatty acid Phosphatidyl Ethanol Ethanol Ethyl Palmitate (16:0) Fatty Acid Ethyl Esters Hours A. Helander and O. Beck, 2004 EtOH mmol/L normalized EtS µmol/mmol normalized EtG µmol/mmol Concentrations following Ethanol dose of 0.5 g/kg Drugs of Abuse Testing Facts vs. Fiction Dopamine MDMA “Ecstasy” Amphetamine Methamphetamine Noradrenaline
- oral fluid