Lab Testing for Substance Use Neeral K Sheth

Lab Testing for Substance Use Neeral K. Sheth, D. O. , F. A. P. A Assistant Professor Department of Psychiatry and Behavioral Sciences Rush Medical College © AMSP 2020 1

Substance Use (SU) in the U. S. 2018 National Survey: 140 million used Et. OH past mo. 53 million used illicit substance past yr. 20 million w/ substance problems past yr. © AMSP 2020 2

Lab Testing in Many Settings Legal/Criminal Preemployment Athletics Medical © AMSP 2020 3

Physicians Should Know: Reasons to order lab testing Help direct clinical care NOT universally or punitively Methods of drug testing Interpretation of urine testing © AMSP 2020 4

This Lecture Reviews Definitions Role of lab testing Drug-specific concerns Limitations © AMSP 2020 5

Substance Use Disorder (SUD) 2+ symptoms in 12 months ↑ Amts/↑ time than intend Role failure Unable to ↓ use Hazardous use ↑ Time obtain/use/recover Craving ↓ Activities to use/recover Tolerance Use despite problems Withdrawal Social/interpers problems © AMSP 2020 6

Substance Intoxication Recent ingestion Problematic ∆s Physiologic Behavioral Psychological Effects of drugs on brain © AMSP 2020 7

Substance Withdrawal Sx opposite of acute drug effect Cessation (or ↓) of substance Et. OH as example: 2+ days of following: ↑ BP, +/or pulse, +/or sweating Hand tremor Insomnia Nausea +/or vomiting Anxiety © AMSP 2020 8

Other Technical Definitions Metabolite = Breakdown product of drug Pharmacokinetics = Body’s action on drug Absorption Distribution Metabolism Elimination Half-life = Drug in body decreased by ½ © AMSP 2020 9

This Lecture Reviews Definitions Role of lab testing in substance use Drug-specific concerns w/ urine testing Limitations © AMSP 2020 10

Lab Testing Useful if Suspicion for SU History of misuse Family or partner with SUD Ongoing problems suggesting use Physical exam Poor grooming/hygiene/weight ↓ Signs of IV drug use Intoxication © AMSP 2020 11

Lab Testing for SU Affected By: Pharmacokinetics False neg if conc. too low Testing before drug absorbed Detection Strategy Direct measure drug or metabolite Indirect effect (e. g. , liver changes) Test: urine, blood, sweat, hair, nails, saliva © AMSP 2020 12

Urine Testing Standard screen: antibody (ab) immunoassay Ab binds to molecules rxn = drug present Asset: non-invasive, quick, cheap Liability: false results, cheating, variability Mass spectrometry (MS) confirmation Asset: ↑ specificity drugs/metabolites Liability: $$$, time-consuming, needs expert © AMSP 220 13

Blood Testing- Direct Biomarkers Assets Quantifies amt substance consumed Monitors conc. ∆s over time Results quickly available Liabilities Detects recent ingestion only Negative after short period of abstinence © AMSP 2020 14

Example: Blood Alcohol Concentration (BAC) Determines amt of Et. OH used Monitor ∆s in BAC over time BAC predicts impairment 0. 05% (0. 05 g/100 ml blood) = ↓coord. 0. 08% = legal driving limit 0. 40% = coma / death may occur © AMSP 2020 15

Blood Testing: Indirect Markers Assets Detects heavy, chronic use Abstinence → slow return to normal Liabilities False ↑ from meds, health, etc. Test result take long © AMSP 2020 16

Indirect Marker Examples Liver function tests Aspartate aminotransferase (AST) Alanine aminotransferase (ALT) Mean corpuscular volume (MCV) Red blood cell size MCV ↑ w/ chronic, heavy drinking Abstinence ↓ MCV over 3 months © AMSP 2020 17

Sweat Testing Swab collection To verify intoxication Detects use only <24 hrs Patch collection Collect drug over longer time (~1 wk) Drugs might be reabsorbed into skin Assets: difficult to cheat, electric monitoring Liabilities: Limited quantification, exercise effects AMSP 18

Hair Testing Hairs cut and sent for testing Assets Difficult to cheat Detects patterns of long-term use Liabilities Tests few drugs w/ long wait for results Requires expensive replication if positive False-negatives from hair treatments © AMSP 2020 19

Saliva Testing Drug from blood or oral intake presence in saliva Saliva absorbed into pad Assets Difficult to cheat Can detect acute intoxication Liabilities Only detects for < 24 hours Requires expensive replication if positive © AMSP 2020 20

Nail Testing Drugs in nail bed via blood layers of history in nail Assets Stable and easy to ship/store Detects 3 -6 mts after use; chronic use Detects prenatal drug exposure Liabilities False positive from environment Not detect single use © AMSP 2020 21

This Lecture Reviews Definitions Role of lab testing in substance use Drug-specific concerns w/ urine testing Limitations © AMSP 2020 22

UDS: Most Common Test Manufacturers create diff UDS Detection variable b/w products Therefore, best practice Contact lab for info about UDS Ask for assistance w/ interpretation © AMSP 2020 23

Cannabis Screen Tetrahydrocannabinol (THC) = 1º component UDS detects inactive THC metabolite THC stored in fat slowly released into blood Detected 3 -5 d (rare use); 10 -30 d (chronic use) Past use ID’ed ≠ intoxication or impairment Efavirenz, pantoprazole* false-positives *Dronabinol © AMSP 2020 24

Opioid Screen UDS detects morphine & codeine (natural opiates) Other opioids +/- on screens Hydrocodone (in Norco) Hydromorphone (Dilaudid) Oxycodone (Oxy. Contin) Detected for 1 -2 d Positive result w/ heroin Heroin 6 -monoacetylmorphone* morphine © AMSP 2020 25

False-Positives on Opioid Screen Dextromethorphan (Robitussin) Diphenhydramine (Benadryl) Poppy seeds Verapamil (Isoptin) Rifampin (Rifadin) © AMSP 2020 26

Other Opioids Methadone (Methadose) Buprenorphine (Suboxone) Oxymorphone (Opana) Fentanyl (Duragesic) Metabolites don’t include morphine or codeine False-negative on UDS Specific opioid needs to be ordered Detection times vary: Methadone (11 d); buprenorphine (4 d) © AMSP 2020 27

Benzodiazepine (Bz) Screen (1) Each test is unique difficult to interpret Detects oxazepam (Serax) itself Or as metabolite of diazepam (Valium) If no oxazepam metabolite false-negative Alprazolam (Xanax) Lorazepam (Ativan) Bz-like sleep meds false-negative Eszopiclone (Lunesta) Zolpidem (Ambien) Many bz require specific testing © AMSP 2020 28

Bz Screen (2) Long half-live bzs (i. e. , diazepam) Detected up to 30 days Short half-live bzs (i. e. , lorazepam) Detected up to 3 days False-positives include Sertraline (Zoloft) Oxaprozin (Daypro) Efavirenz (Sustiva) © AMSP 2020 29

Amphetamine Urine Screen Amphetamine/methamphetamine (meth) Detects amphetamine (meth metabolite) MS confirmation to ID meth Detected 1 d; 2 -4 d (chronic use) © AMSP 2020 30

Many False-Positives OTC decongestants Psych meds: bupropion (Wellbutrin) ADHD meds: amphetamine (Adderall) Methylphenidate (Ritalin & Concerta) ≠ false-positive © AMSP 2020 31

Cocaine Screen Detects benzoylecgonine (1º metabolite) Coca tea positive b/c contains cocaine ø Cross-reactivity w/ other substances Detected 2 -4 d © AMSP 2020 32

Phencyclidine (PCP) Screen False-positives Dextromethorphan (Robitussin) Ibuprofen (Advil) Tramadol (Ultram) Venlafaxine (Effexor) Detected 1 -8 d (rare use); 21 d (chronic use) © AMSP 2020 33

This Lecture Reviews Definitions Role of lab testing in substance use Drug-specific concerns w/ urine testing Limitations © AMSP 2020 34

Many Drugs Undetected on UDS Synthetic marijuana (e. g. , spice) ≠ THC metabolites 3, 4 methylenedioxymethamphetamine (MDMA) False-negative amphetamines screen © AMSP 2020 35

Common Clinician Errors Using UDS to r/o drug use Many drugs not tested Not knowing drugs tested by hospital Miss false-positives Cross reactivity, contamination Miss false-negatives ↓ drug levels, tampering © AMSP 2020 36

Urine Sample Tampering (1) Adulterants disrupt UDS OTC eye drops, ammonia Dilution ↑ fluid intake Lowers drug concentration in urine © AMSP 2020 37

Urine Sample Tampering (2) Substitution Use other’s, old, or synthetic urine False attribution Claim false-positive from rx’ed med © AMSP 2020 38

Takeaways 1) Various methods of testing available Urine & blood common 2) Direct and indirect testing helpful Pros and cons 3) Many limitations of UDS False results, tampering, difficult to interpret 4) Knowing limitations guides assessment © AMSP 2020 39

Acknowledgements Marc A. Schuckit, M. D. Brooke J. Arterberry, Ph. D. & Other AMSP Scholars www. alcoholmedicalscholars. org © AMSP 2020 40