-
Potential false positives May cause false-positive result on amphetamines immunoassay: - amantadine1
- aripiprazole2
- atomoxetine3
- brompheniramine4
- bupropion5
- chloroquine phosphate6
- chlorpromazine4
- desipramine1
- desvenlafaxine7
- ephedrine8
- labetalol9
- metformin10
- methylphenidate11
- phentermine hydrochloride12
- phenylephrine13
- promethazine14
- pseudoephedrine8
- thioridazine12
- trazodone15
- trimethobenzamide16
- venlafaxine17
Footnotes 1 Merigian KS, Browning RG. Desipramine and amantadine causing false-positive urine test for amphetamine. Ann Emerg Med. 1993 Dec;22(12):1927-8.
2 Kaplan J, et al. Case Reports of Aripiprazole Causing False-Positive Urine Amphetamine Drug Screens in Children. Pediatrics. 2015 Dec;136(6):e1625-8. PubMed® abstract
3 Fenderson JL, et al. Amphetamine positive urine toxicology screen secondary to atomoxetine. Case Rep Psychiatry. 2013:2013:381261. Free, full-text PDF
4 Olsen KM, et al. Metabolites of chlorpromazine and brompheniramine may cause false-positive urine amphetamine results with monoclonal EMIT d.a.u. immunoassay. Clin Chem. 1992 Apr;38(4):611-2.
5 Wellbutrin SR. Prescribing information. GlaxoSmithKline; 2022.
6 Gomila I, et al. Cross-Reactivity of Chloroquine and Hydroxychloroquine With DRI Amphetamine Immunoassay. Ther Drug Monit. 2017 Apr;39(2): 192-196. PubMed® abstract
7 Pristiq. Prescribing information. Pfizer Inc; 2023.
8 Stout PR, et al. Evaluation of ephedrine, pseudoephedrine and phenylpropanolamine concentrations in human urine samples and a comparison of the specificity of DRI amphetamines and Abuscreen online (KIMS) amphetamines screening immunoassays. J Forensic Sci. 2004 Jan;49(1):160-4. PubMed® abstract
9 Labetalol. Prescribing information. Par Pharmaceutical, Inc; 2017.
10 Fucci N. False positive results for amphetamine in urine of a patient with diabetes mellitus. Forensic Sci Int. 2012 Nov 30;223(1-3):e60.
11 Manzi S, et al. Methylphenidate produces a false-positive urine amphetamine screen. Pediatr Emerg Care. 2002 Oct;18(5):401.
12 Moeller KE, et al. Clinical Interpretation of Urine Drug Tests: What Clinicians Need to Know About Urine Drug Screens. Mayo Clin Proc. 2017 May;92(5):774-796. Free, full-text PDF
13 Curtin LB, Cawley MJ. Immunoassay cross-reactivity of phenylephrine and methamphetamine. Pharmacotherapy. 2012 May;32(5):e98-102. PubMed® abstract
14 Melanson SEF, et al. Reduced interference by phenothiazines in amphetamine drug of abuse immunoassays. Arch Pathol Lab Med. 2006 Dec;130(12):1834-8. Free, full-text article
15 Baron JM, et al. The trazodone metabolite meta-chlorophenylpiperazine can cause false-positive urine amphetamine immunoassay results. J Anal Toxicol. 2011 Jul;35(6):364-8. PubMed® abstract
16 Jones R, et al. Trimethobenzamide cross-reacts in immunoassays of amphetamine/methamphetamine. Clin Chem. 1993 Apr;39(4):699-700.
17 Effexor XR. Prescribing information. Viatris Inc; 2023.
-
Medications that may not be detected BZD immunoassays are limited by high cutoff values and/or inability to detect conjugated metabolites; most immunoassays detect free or nonconjugated oxazepam or nordiazepam forms (common metabolites of several BZDs). Not reliably detected w/ BZD immunoassay: - alprazolam
- clonazepam
- lorazepam
Footnotes 1 Moeller KE, et al. Clinical Interpretation of Urine Drug Tests: What Clinicians Need to Know About Urine Drug Screens. Mayo Clin Proc. 2017 May;92(5):774-796. Free, full-text PDF
Potential false positives May cause false-positive result on BZD immunoassay: - efavirenz1
- oxaprozin2
- sertraline3
Footnotes 1 Blank A, et al. Efavirenz treatment and false-positive results in benzodiazepine screening tests. Clin Infect Dis. 2009 Jun 15;48(12):1787-9. Free, full-text article
2 Daypro. Prescribing information. Pfizer Inc; 2022.
3 Zoloft. Prescribing information. Viatris Inc; 2023.
-
Medications that may not be detected Cannabinoid immunoassay screens for THC metabolite 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid; synthetic cannabinoids in spice, K2 will not be detected w/ this test.
Footnotes 1 Moeller KE, et al. Clinical Interpretation of Urine Drug Tests: What Clinicians Need to Know About Urine Drug Screens. Mayo Clin Proc. 2017 May;92(5):774-796. Free, full-text PDF
• Passive marijuana exposure resulted in THC metabolite urine concentrations below standard cutoffs
Potential false positives May cause false-positive result on cannabinoid immunoassay: - baby wash products1
- efavirenz2
- ibuprofen3
- naproxen3
- PPIs4
Footnotes 1 Cotten SW, et al. Unexpected interference of baby wash products with a cannabinoid (THC) immunoassay. Clin Biochem. 2012 Jun;45(9):605-9. Free, full-text article
2 Efavirenz. Prescribing information. Aurobindo Pharma Ltd; 2023.
3 Rollins DE, et al. Investigation of interference by nonsteroidal anti-inflammatory drugs in urine tests for abused drugs. Clin Chem. 1990 Apr;36(4):602-6. PubMed® abstract
4 Moeller KE, et al. Clinical Interpretation of Urine Drug Tests: What Clinicians Need to Know About Urine Drug Screens. Mayo Clin Proc. 2017 May;92(5):774-796. Free, full-text PDF
• Mechanism by which PPIs interfere w/ cannabinoid immunoassay unknown; literature limited to 1 case report w/ pantoprazole; unclear if class effect exists
• Definitive tests unable to distinguish between plant THC and dronabinol (synthetic THC)
-
Medications that may not be detected Most immunoassays for synthetic cannabinoids are nonspecific, detect metabolites; no standard cutoff value exists; synthetic compounds continuously changed/created and may not be detected.
Footnotes 1 Moeller KE, et al. Clinical Interpretation of Urine Drug Tests: What Clinicians Need to Know About Urine Drug Screens. Mayo Clin Proc. 2017 May;92(5):774-796. Free, full-text PDF
Potential false positives May cause false-positive result on synthetic cannabinoids immunoassay: Footnotes 1 Moeller KE, et al. Clinical Interpretation of Urine Drug Tests: What Clinicians Need to Know About Urine Drug Screens. Mayo Clin Proc. 2017 May;92(5):774-796. Free, full-text PDF
-
Medications that may not be detected Standard opiate immunoassays test for opium alkaloids and/or metabolites, incl. morphine/codeine. Semisynthetic opioids may or may not be detected, and synthetic opioids will not be detected by opiate immunoassay; assays specific for these drugs may be requested.1 Semisynthetic opioids: - buprenorphine: screens negative on opiate immunoassay1-5
- hydrocodone: may screen negative on opiate immunoassay1,2,4
- hydromorphone: may screen negative on opiate immunoassay1-4
- oxycodone: typically screens negative on opiate immunoassay (w/ exception of large amounts)1-4,6
- oxymorphone: typically screens negative on opiate immunoassay1-4
Synthetic opioids: screen negative on opiate immunoassay - fentanyl1-5
- meperidine2,5
- methadone1-5
- tramadol1,2
Footnotes 1 Raouf M, et al. A Practical Guide to Urine Drug Monitoring. Fed Pract. 2018 Apr;35(4):38-44. Free, full-text PDF
2 Moeller KE, et al. Clinical Interpretation of Urine Drug Tests: What Clinicians Need to Know About Urine Drug Screens. Mayo Clin Proc. 2017 May;92(5):774-796. Free, full-text PDF
3 Argoff CE, et al. Rational Urine Drug Monitoring in Patients Receiving Opioids for Chronic Pain: Consensus Recommendations. Pain Med. 2018 Jan 1;19(1):97-117. Free, full-text PDF
4 Substance Abuse and Mental Health Services Administration. Medications for Opioid Use Disorder. Treatment Improvement Protocol (TIP) Series 63 Publication No. PEP21-02-01-002. Rockville, MD: Substance Abuse and Mental Health Services Administration, 2021. Free, full-text PDF
5 Jarvis M, et al. Appropriate Use of Drug Testing in Clinical Addiction Medicine. J Addict Med. 2017 May/Jun;11(3):163-173. Free, full-text PDF
6 Kapur BM, Aleksa K. What the lab can and cannot do: clinical interpretation of drug testing results. Crit Rev Clin Lab Sci. 2020 Dec;57(8):548-585. Free, full-text ePDF
Potential false positives May cause false-positive result on opiate immunoassay: - dextromethorphan1
- fluoroquinolones1
- olanzapine/samidorphan2
- poppy seeds1
- quinine sulfate1
- rifampin3
May cause false-positive result on methadone immunoassay: - clomipramine4
- chlorpromazine4
- diphenhydramine4
- doxylamine4
- quetiapine4
- thioridazine4
- verapamil4
May cause false-positive result on buprenorphine immunoassay: Footnotes 1 Moeller KE, et al. Clinical Interpretation of Urine Drug Tests: What Clinicians Need to Know About Urine Drug Screens. Mayo Clin Proc. 2017 May;92(5):774-796. Free, full-text PDF
• Opiate cutoff established by SAMHSA for Federal Workplace Drug Testing Guidelines limits false positives from poppy seed ingestion
2 Lybalvi. Prescribing information. Alkermes, Inc; 2024.
3 Rifadin. Prescribing information. sanofi-aventis U.S. LLC; 2023.
4 Methadose. Prescribing information. Hikma Pharmaceuticals USA Inc; 2023.
5 Substance Abuse and Mental Health Services Administration. Medications for Opioid Use Disorder. Treatment Improvement Protocol (TIP) Series 63 Publication No. PEP21-02-01-002. Rockville, MD: Substance Abuse and Mental Health Services Administration, 2021. Free, full-text PDF
-
Potential false positives May cause false-positive result on PCP immunoassay: - desvenlafaxine1
- dextromethorphan2
- diphenhydramine2
- doxylamine3
- ibuprofen4
- imipramine5
- ketamine6
- lamotrigine7
- methylenedioxypyrovalerone (MDPV) or “bath salts”8
- meperidine5
- thioridazine5
- tramadol2
- venlafaxine9
Footnotes 1 Pristiq. Prescribing information. Pfizer Inc; 2023.
2 Rengarajan A, Mullins ME. How often do false-positive phencyclidine urine screens occur with use of common medications? Clin Toxicol (Phila). 2013 Jul;51(6):493-6. Free, full-text PDF
3 Bonjesta. Prescribing information. Duchesnay Inc; 2022.
4 Marchei E, et al. Are false-positive phencyclidine immunoassay instant-view multi-test results caused by overdose concentrations of Ibuprofen, metamizol, and dextromethorphan? Ther Drug Monit. 2007 Oct;29(5):671-3. Article preview
5 Moeller KE, et al. Clinical Interpretation of Urine Drug Tests: What Clinicians Need to Know About Urine Drug Screens. Mayo Clin Proc. 2017 May;92(5):774-796. Free, full-text PDF
6 Shannon M. Recent ketamine administration can produce a urine toxic screen which is falsely positive for phencyclidine. Pediatr Emerg Care. 1998 Apr;14(2):180.
7 Geraci MJ, et al. Phencyclidine false positive induced by lamotrigine (Lamictal®) on a rapid urine toxicology screen. Int J Emerg Med. 2010 Nov 6;3(4):327-31. Free, full-text PDF
8 Macher AM, Penders TM. False-positive phencyclidine immunoassay results caused by 3,4-methylenedioxypyrovalerone (MDPV). Drug Test Anal. 2013 Feb;5(2):130-2.
9 Effexor XR. Prescribing information. Viatris Inc; 2023.
|