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Urine Drug Screening: What Pediatric Clinicians Need to Know to Optimize Patient Care

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        You must receive 70% correct responses to receive the certificate.
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        Tests will be accepted until August 31, 2022.

      OBJECTIVES

      • 1.
        State the differences of the most common urine drug screening testing modalities: immunoassay and gas chromatography/mass spectrometry.
      • 2.
        Describe common causes of false-positive and false-negative urine drug testing results and the detection window of specific medications.
      • 3.
        Identify common caveats when interpreting urine drug testing result.
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      OVERVIEW OF URINE DRUG SCREENING

      Urine drug screening (UDS) is a laboratory test frequently used to screen for drugs of abuse, monitor for medication compliance, evaluate for suspected drug intoxication or overdose, and in office-based pain contracts (
      • Kale N.
      Urine drug tests: Ordering and Interpreting Results.
      ;
      • Standridge J.B.
      • Adams S.M.
      • Zotos A.P.
      Urine drug screening: A valuable office procedure.
      ). In children and adolescents, UDS may be used to prevent substance use, evaluate for suspected drug use or intoxication, or as part of substance abuse treatment (
      • Levy S.
      • Siqueira L.M.
      • Ammerman S.D.
      • Gonzalez P.K.
      • Ryan S.A.
      • Smith V.C.
      Committee on Substance Abuse
      Testing for drugs of abuse in children and adolescents.
      ). When using UDS as a tool to make clinical decisions about high-risk medications, it is important to understand the differences between UDS testing modalities, common causes of false-positive or false-negative results, and the detection window of specific medications. There are two commonly used types of UDS available: immunoassay and gas chromatography/mass spectrometry (GC-MS;
      • Kale N.
      Urine drug tests: Ordering and Interpreting Results.
      ).
      Immunoassays are the most frequently used initial UDS modality because they are simple to use, easy to automate, and provide rapid results. Immunoassays are a qualitative test that identifies the presence of substances above a set threshold through antibody complex that binds with a drug, metabolite, or class of compounds (
      • Jarvis M.
      • Williams J.
      • Hurford M.
      • Lindsay D.
      • Lincoln P
      • Giles L.
      • Safarian T.
      Appropriate use of drug testing in clinical addiction medicine.
      ). Immunoassays allow for point of care testing and are typically used as the initial UDS because of their low cost, rapid results, and convenience. Because of poor specificity and the risk of false-positive results, positive immunoassay results should be considered presumptive and followed by GC-MS for confirmation (
      • Kale N.
      Urine drug tests: Ordering and Interpreting Results.
      ;
      • Standridge J.B.
      • Adams S.M.
      • Zotos A.P.
      Urine drug screening: A valuable office procedure.
      ). GC-MS is a laboratory-based test that separates medications on the basis of polarity to detect substances (
      • Standridge J.B.
      • Adams S.M.
      • Zotos A.P.
      Urine drug screening: A valuable office procedure.
      ). Although GC-MS is more costly and time-consuming, it provides higher sensitivity and specificity (Jarvis et al., 2019;
      • Kale N.
      Urine drug tests: Ordering and Interpreting Results.
      ;
      • Schwebach A.
      • Ball J.
      Urine drug screening: Minimizing false-positives and false-negatives to optimize patient care.
      ).
      UDS requires cutoff values to be met to be considered positive. Results lower than the established cutoff are reported as negative, but it does not necessarily mean that the substance was not present. Therefore, a negative result indicates the concentration was lower than the established cutoff. When evaluating a UDS, it is also important to consider time because of the ingestion and window of detection. After a substance is used, it takes approximately 2 hr to become detectable in the urine (
      • Jarvis M.
      • Williams J.
      • Hurford M.
      • Lindsay D.
      • Lincoln P
      • Giles L.
      • Safarian T.
      Appropriate use of drug testing in clinical addiction medicine.
      ). This factor is crucial for patients who present acutely ill after recent suspected ingestion. Although it would still be indicated to obtain a UDS, the test results must be interpreted cautiously.
      The window of detection is the amount of time a substance can be detected in the urine and still produce a positive result. To evaluate the detection window, clinicians should consider both drug and patient characteristics. Drug characteristics that affect the detection window include half-life, metabolites, drug interactions, dosing interval, low versus high dose, chronic versus occasional use, and time of last ingestion. Patient-specific factors include body mass, pH of the urine, urine concentration, and renal or liver impairment (
      • Moeller K.E.
      • Lee K.C.
      • Kissack J.C.
      Urine drug screening: Practical guide for clinicians.
      ). Table 1 lists the window of detection in the urine for drugs routinely screened for in UDS. The Department of Health and Human Services has standardized cutoff values for use in the workplace; however, institutions may use lower values in practice. Clinicians should confirm cutoff values with their institution's laboratory before the interpretation of results.
      TABLE 1Window of detection in the urine
      SubstanceTime
      Amphetamines2–3 days
      Benzodiazepines
       Short-acting3–5 days
       Long-acting30 days
      Cocaine2–4 days
      Marijuana
       Single-use2 days
       Moderate use (3 times/week)2 weeks
       Daily use/Long-term heavy use4–6 weeks
      Opioids
       Buprenorphine11 days
       Codeine1–2 days
       Fentanyl2–3 days
       Heroin1–2 days
       Hydromorphone1–2 days
       Methadone3–4 days
       Morphine3 days
       Oxycodone1–3 days
       Tramadol2–4 days
      Note.
      • Levy S.
      • Siqueira L.M.
      • Ammerman S.D.
      • Gonzalez P.K.
      • Ryan S.A.
      • Smith V.C.
      Committee on Substance Abuse
      Testing for drugs of abuse in children and adolescents.
      ).

      WHEN TO SCREEN FOR DRUGS OF ABUSE IN CHILDREN AND ADOLESCENTS

      The American Society of Addiction Medicine (ASAM) and American Academy of Pediatrics (AAP) does not recommend routine UDS by clinicians in the absence of suspicion for substance use (
      • Jarvis M.
      • Williams J.
      • Hurford M.
      • Lindsay D.
      • Lincoln P
      • Giles L.
      • Safarian T.
      Appropriate use of drug testing in clinical addiction medicine.
      ;
      • Levy S.
      • Siqueira L.M.
      • Ammerman S.D.
      • Gonzalez P.K.
      • Ryan S.A.
      • Smith V.C.
      Committee on Substance Abuse
      Testing for drugs of abuse in children and adolescents.
      ). Neither group supports home UDS by parents because of the risk of misinterpretation and limited evidence that home UDS reduces adolescent drug use (
      • Jarvis M.
      • Williams J.
      • Hurford M.
      • Lindsay D.
      • Lincoln P
      • Giles L.
      • Safarian T.
      Appropriate use of drug testing in clinical addiction medicine.
      ;
      • Levy S.
      • Siqueira L.M.
      • Ammerman S.D.
      • Gonzalez P.K.
      • Ryan S.A.
      • Smith V.C.
      Committee on Substance Abuse
      Testing for drugs of abuse in children and adolescents.
      ). The ASAM and AAP recommend screening children and adolescents for emergent clinical care, assessment of behavioral or mental health symptoms, in substance abuse programs, or as a deterrent for use in the juvenile probation system (
      • Levy S.
      • Siqueira L.M.
      • Ammerman S.D.
      • Gonzalez P.K.
      • Ryan S.A.
      • Smith V.C.
      Committee on Substance Abuse
      Testing for drugs of abuse in children and adolescents.
      ). UDS is useful for clinicians to identify potential toxins in patients who present with altered mental status. The AAP recommends obtaining a UDS if there is a concern for accidental or intentional ingestion, unexplained seizures, syncope, arrhythmias, or the presence of toxidromes (
      • Levy S.
      • Siqueira L.M.
      • Ammerman S.D.
      • Gonzalez P.K.
      • Ryan S.A.
      • Smith V.C.
      Committee on Substance Abuse
      Testing for drugs of abuse in children and adolescents.
      ). The ASAM identifies those with a known history of substance use or trauma, in treatment for mental health disorders, or declining academic performance as a high-risk population that may benefit from early detection of substance use (
      • Levy S.
      • Siqueira L.M.
      • Ammerman S.D.
      • Gonzalez P.K.
      • Ryan S.A.
      • Smith V.C.
      Committee on Substance Abuse
      Testing for drugs of abuse in children and adolescents.
      ). High-risk patients suspected of having recent or ongoing drug use (by parent or clinician) should be screened by clinicians, particularly if the patient also presents with fatigue, moodiness, or school failure (
      • Levy S.
      • Siqueira L.M.
      • Ammerman S.D.
      • Gonzalez P.K.
      • Ryan S.A.
      • Smith V.C.
      Committee on Substance Abuse
      Testing for drugs of abuse in children and adolescents.
      ). Screening may not be necessary if a patient is honest about substance use history, though it may provide added value. If a child or adolescent denies substance use but shows concerning signs/symptoms of substance use, screening should still be performed.

      CAVEATS WHEN INTERPRETING TEST RESULTS

      Accurate interpretation of UDS is crucial as misinterpretation may lead to adverse consequences, such as criminal charges, loss of a job, loss of trust from health care professionals, or discontinuation of chronic pain contracts. In children and adolescents, misinterpretation may result in mistrust or tension from parents. To decrease the likelihood of inaccurate interpretation, health care professionals performing these tests should be familiar with common causes of false-positive results (Table 2) or negative results and signs of adulteration. Before performing UDS, providers should obtain a list of all prescription, over-the-counter, and herbal medications to fully assess UDS results (
      • Schwebach A.
      • Ball J.
      Urine drug screening: Minimizing false-positives and false-negatives to optimize patient care.
      ).
      TABLE 2Medications commonly causing false-positive results on immunoassay
      MedicationsAmphetamine/MethamphetamineBenzodiazepinesCannabinoidMethadoneOpioids
      Over-the-counter products
       BrompheniramineX
       DextromethorphanX
       DiphenhydramineX
       DoxylamineXX
       IbuprofenX
       NaproxenX
       PantoprazoleX
       PseudoephedrineX
       RanitidineX
       Vicks nasal inhalerX
      Antidepressants/antipsychotics
       BupropionX
       ChlorpromazineXX
       DesipramineX
       DoxepinX
       FluoxetineX
       QuetiapineX
       SertralineX
       TrazodoneX
      Other agents
       EfavirenzXX
       EphedrineX
       FluoroquinolonesX
       LabetalolX
       MetforminX
       MethylphenidateX
       PromethazineX
       QuinolonesX
       SelegilineX
       VerapamilX
      Note.
      • Brahm N.C.
      • Yeager L.L.
      • Fox M.D.
      • Farmer K.C.
      • Palmer T.A.
      Commonly prescribed medications and potential false-positive urine drug screens.
      ;
      • Levy S.
      • Siqueira L.M.
      • Ammerman S.D.
      • Gonzalez P.K.
      • Ryan S.A.
      • Smith V.C.
      Committee on Substance Abuse
      Testing for drugs of abuse in children and adolescents.
      );
      • Moeller K.E.
      • Lee K.C.
      • Kissack J.C.
      Urine drug screening: Practical guide for clinicians.
      );
      • Moeller K.E.
      • Kissack J.C.
      • Atayee R.S.
      • Lee K.C.
      Clinical interpretation of urine drug tests: What clinicians need to know about urine drug screens.
      ).
      Adulterating, substituting, and diluting urine is commonly done to avoid detection of drug use (
      • Moeller K.E.
      • Lee K.C.
      • Kissack J.C.
      Urine drug screening: Practical guide for clinicians.
      ). It is critical that clinicians evaluate all urine samples’ color, appearance, pH, and specific gravity to screen for signs of adulteration. Patients may intentionally adulterate their urine by adding vinegar, soap, bleach, drain cleaner, eye drops, salt, ammonia, or products containing peroxide (
      • Schwebach A.
      • Ball J.
      Urine drug screening: Minimizing false-positives and false-negatives to optimize patient care.
      ). Changes in urine pH, specific gravity, or appearance should prompt further investigation for adulteration (
      • Schwebach A.
      • Ball J.
      Urine drug screening: Minimizing false-positives and false-negatives to optimize patient care.
      ). Patients may also drink excessive amounts of water (2–4 quarts) in an attempt to dilute urine drug concentrations and decrease the likelihood of detection (
      • Schwebach A.
      • Ball J.
      Urine drug screening: Minimizing false-positives and false-negatives to optimize patient care.
      ). Normal urine specimens should range from pale yellow to clear and should be collected early in the morning to provide the most concentrated urine, with temperature ranges from 32°C to 38°C (
      • Moeller K.E.
      • Lee K.C.
      • Kissack J.C.
      Urine drug screening: Practical guide for clinicians.
      ). The temperature of urine samples should promptly be measured and recorded after collection to screen for urine substitution. Urine pH normally ranges from 4.5 to 8 throughout the day. Specimen adulteration should be suspected if the urine pH is < 3 or > 11, or if the specific gravity is < 1.002 or > 1.020 (
      • Moeller K.E.
      • Lee K.C.
      • Kissack J.C.
      Urine drug screening: Practical guide for clinicians.
      ).
      Medications with similar chemical structures may lead to a cross-reactivity on immunoassays, resulting in a false-positive result (
      • Schwebach A.
      • Ball J.
      Urine drug screening: Minimizing false-positives and false-negatives to optimize patient care.
      ). The occurrence of false-positive results is influenced by the sensitivity and specificity of the immunoassay being used. Minimizing the use of medications that commonly cause false-positive test results may be useful in patients who require frequent UDS but should be carefully weighed against the efficacy, cost, and adverse effect profile of the alternative treatment (
      • Schwebach A.
      • Ball J.
      Urine drug screening: Minimizing false-positives and false-negatives to optimize patient care.
      ). In addition, patients may adulterate their urine with prescribed medications by “pill dipping” or “pill shaving.” A patient who diverts medications may save a small amount to “dip” or “shave” into the urine, leading to a false-positive presumptive test. This issue can be problematic when the parent compound is tested for in the urine, making clinicians unable to differentiate adulteration versus compliance. When the parent compound is not excreted in the urine, adulteration should be suspected.
      False-negative results may occur when urine drug concentrations are below the cutoff. This result can be because of the quantity of drug ingested, the time between ingestion and UDS performed, or urine adulteration. Another risk for false-negative results is poor cross-reactivity of medications within the immunoassay. Metabolites of parent drugs are commonly used for the detection of benzodiazepines and opioids. Patients may be prescribed medications of the same class that do not follow the specific metabolic pathway tested by the immunoassay, causing higher rates of false-negative results (
      • Schwebach A.
      • Ball J.
      Urine drug screening: Minimizing false-positives and false-negatives to optimize patient care.
      ).

      REVIEW OF MAJOR MEDICATION CLASSES

      Amphetamines

      Amphetamine immunoassays detect amphetamines, amphetamine isomers, methamphetamine, and other amine-containing compounds (
      • Moeller K.E.
      • Kissack J.C.
      • Atayee R.S.
      • Lee K.C.
      Clinical interpretation of urine drug tests: What clinicians need to know about urine drug screens.
      ). Immunoassays for amphetamines will return positive after amphetamine, dexamphetamine, and lisdexamfetamine use. Methylphenidate does not cross-react with amphetamines on immunoassay, so testing should be completed with GC-MS (
      • Breindahl T.
      • Hindersson P.
      Methylphenidate is distinguished from amphetamine in drug-of-abuse testing.
      ). Unfortunately, immunoassays for amphetamines commonly result in false positives because of a high rate of cross-reacting medications. Medications commonly linked to false-positive results include bupropion, phenothiazines, tricyclic antidepressants, trazodone, pseudoephedrine, ephedrine, ranitidine, and ofloxacin (
      • Nomier M.
      • Al-Huseini H.
      False-positive TDxFLx urine amphetamine/methamphetamine II assay from ofloxacin.
      ), and labetalol (
      • Moeller K.E.
      • Kissack J.C.
      • Atayee R.S.
      • Lee K.C.
      Clinical interpretation of urine drug tests: What clinicians need to know about urine drug screens.
      ). In addition, dimethylamylamine, a widely used energy supplement, causes false-positive amphetamine screens (
      • Vorce S.P.
      • Holler J.M.
      • Cawrse B.M.
      • Magluilo J.
      Dimethylamylamine: A drug causing positive immunoassay results for amphetamines.
      ). Structural similarities are the most common reason for false positives (
      • Moeller K.E.
      • Lee K.C.
      • Kissack J.C.
      Urine drug screening: Practical guide for clinicians.
      ). Vicks nasal inhaler contains an isomer of methamphetamine (l-methamphetamine) that does not cause euphoric effects, leading to potential cross-reactivity on immunoassay (
      • Moeller K.E.
      • Lee K.C.
      • Kissack J.C.
      Urine drug screening: Practical guide for clinicians.
      ). Selegiline metabolism also produces l-amphetamine and l-methamphetamine, contributing to false-positive UDS results (
      • Moeller K.E.
      • Kissack J.C.
      • Atayee R.S.
      • Lee K.C.
      Clinical interpretation of urine drug tests: What clinicians need to know about urine drug screens.
      ).

      Benzodiazepines

      Given the widespread use of benzodiazepines for anxiety and sedation, a thorough history should be obtained before testing. UDS for benzodiazepines frequently results in false-negative results given the inability of the immunoassay to detect conjugated benzodiazepine metabolites and high cutoff values (
      • Moeller K.E.
      • Kissack J.C.
      • Atayee R.S.
      • Lee K.C.
      Clinical interpretation of urine drug tests: What clinicians need to know about urine drug screens.
      ). Immunoassays for benzodiazepines detect the free metabolites oxazepam and nordiazepam, which are metabolites of chlordiazepoxide, temazepam, diazepam, and clorazepate (
      • Moeller K.E.
      • Kissack J.C.
      • Atayee R.S.
      • Lee K.C.
      Clinical interpretation of urine drug tests: What clinicians need to know about urine drug screens.
      ). Benzodiazepines that follow alternative metabolic pathways, such as lorazepam, clonazepam, and alprazolam, have poor cross-reactivity rendering them unable to be detected on UDS (
      • Schwebach A.
      • Ball J.
      Urine drug screening: Minimizing false-positives and false-negatives to optimize patient care.
      ). False-positive results have been reported in patients taking efavirenz and sertraline; therefore, confirmatory GC-MS should be performed in patients with unexplained immunoassay results who report taking these two medications. (
      • Blank A.
      • Hellstern V.
      • Schuster D.
      • Hartmann M.
      • Matthée A.K.
      • Burhenne J.
      • Mikus G.
      Efavirenz treatment and false positive results in benzodiazepine screening test.
      ;
      • Nasky K.M.
      • Cowan G.L.
      • Knittel D.R.
      False-positive urine screening for benzodiazepines: An association with sertraline?: A two-year retrospective chart analysis.
      ).

      Cannabinoids

      Cannabis, also known as marijuana, refers to any part of the cannabis plant (
      • Moeller K.E.
      • Kissack J.C.
      • Atayee R.S.
      • Lee K.C.
      Clinical interpretation of urine drug tests: What clinicians need to know about urine drug screens.
      ). Cannabinoids are a subset of chemicals found within the cannabis plant, with delta-9- tetrahydrocannabinol (THC) being primarily responsible for marijuana's psychoactive properties (
      • Moeller K.E.
      • Lee K.C.
      • Kissack J.C.
      Urine drug screening: Practical guide for clinicians.
      ). Estimating THC's window of detection after marijuana use is complex, as it is influenced by the route of administration, potency of marijuana, frequency of use, body mass, and one's metabolic rate (
      • Moeller K.E.
      • Kissack J.C.
      • Atayee R.S.
      • Lee K.C.
      Clinical interpretation of urine drug tests: What clinicians need to know about urine drug screens.
      ). Chronic users can test positive for over 30 days after cessation, whereas a single-use may only be detectable in the urine up to 3 days (
      • Moeller K.E.
      • Kissack J.C.
      • Atayee R.S.
      • Lee K.C.
      Clinical interpretation of urine drug tests: What clinicians need to know about urine drug screens.
      ). Cannabinoids are available in clinical practice as dronabinol and nabilone for the treatment of chemotherapy-induced vomiting and anorexia in patients with AIDS. Dronabinol is a synthetic THC, which will result in a true-positive result on UDS. Nabilone is a synthetic cannabinoid that is similar to THC. Nabilone follows a different metabolic pathway resulting in negative UDS (
      • Moeller K.E.
      • Kissack J.C.
      • Atayee R.S.
      • Lee K.C.
      Clinical interpretation of urine drug tests: What clinicians need to know about urine drug screens.
      ). Nonsteroidal anti-inflammatory drugs, pantoprazole, and efavirenz have been reported to cross-react with THC on immunoassay (
      • Moeller K.E.
      • Lee K.C.
      • Kissack J.C.
      Urine drug screening: Practical guide for clinicians.
      ). Confirmatory GC-MS should be performed in patients with unexplained immunoassay results who report using nonsteroidal anti-inflammatory drugs, pantoprazole, or efavirenz.

      Cocaine

      UDS for cocaine detects the main metabolite of cocaine, benzoylecgonine (
      • Moeller K.E.
      • Lee K.C.
      • Kissack J.C.
      Urine drug screening: Practical guide for clinicians.
      ). Cross-reactivity rarely exists with cocaine and its metabolites, making the risk of false-positive results relatively nonexistent (
      • Moeller K.E.
      • Kissack J.C.
      • Atayee R.S.
      • Lee K.C.
      Clinical interpretation of urine drug tests: What clinicians need to know about urine drug screens.
      ). Cocaine is available for use in clinical practice as a topical anesthetic in otolaryngology and ophthalmic procedures, which can produce a true-positive UDS result (
      • Moeller K.E.
      • Kissack J.C.
      • Atayee R.S.
      • Lee K.C.
      Clinical interpretation of urine drug tests: What clinicians need to know about urine drug screens.
      ).

      Opioids

      When performing UDS for any reason, it is important to understand that UDS may not detect all opioids. To accurately interpret UDS for opioids, it is critical to understand opioid metabolism. Most immunoassays screen for morphine, codeine, and norcodeine; therefore, morphine, heroin, and codeine use can easily be detected (
      • Schwebach A.
      • Ball J.
      Urine drug screening: Minimizing false-positives and false-negatives to optimize patient care.
      ). Morphine is metabolized to 3-morphine-glucuronide and 6-morphine-glucuronide (
      • Moeller K.E.
      • Kissack J.C.
      • Atayee R.S.
      • Lee K.C.
      Clinical interpretation of urine drug tests: What clinicians need to know about urine drug screens.
      ). Codeine is metabolized in the body to morphine, norcodeine, hydrocodone, and hydromorphone. Codeine, morphine, and norcodeine can be detected in the urine after codeine ingestion; however, hydromorphone and hydrocodone typically are not (
      • Schwebach A.
      • Ball J.
      Urine drug screening: Minimizing false-positives and false-negatives to optimize patient care.
      ).
      Heroin is a semisynthetic derivative of morphine. Heroin is rapidly metabolized to 6-monoacetylmorphine (6-MAM), which is then metabolized to morphine (
      • Moeller K.E.
      • Lee K.C.
      • Kissack J.C.
      Urine drug screening: Practical guide for clinicians.
      ). 6-MAM is a specific metabolite to heroin only, making a positive result definitive for heroin use. However, 6-MAM only has approximately an 8-hr detection window in the urine after heroin use, after which only the morphine metabolite will be detected (
      • Moeller K.E.
      • Kissack J.C.
      • Atayee R.S.
      • Lee K.C.
      Clinical interpretation of urine drug tests: What clinicians need to know about urine drug screens.
      ). Oxycodone is a semisynthetic opioid excreted as oxycodone, oxycodone conjugates, oxymorphone, and noroxycodone, none of which are typically tested for on UDS. Fentanyl lacks metabolites and is usually not detected on UDS (
      • Moeller K.E.
      • Lee K.C.
      • Kissack J.C.
      Urine drug screening: Practical guide for clinicians.
      ). Methadone, a long-acting opioid, is excreted unchanged in the urine and as the metabolite 2-ethylidene-1,5- dimethyl-3,3-diphenylpyrrolidine. UDS uses the parent compound to detect methadone use, making interpretation problematic if a patient adulterates their urine by pill dipping. Confirmatory testing for ethylidene-1,5- dimethyl-3,3-diphenylpyrrolidine presence by GC-MS is necessary if adulteration is suspected. Buprenorphine and methadone are used to treat patients with substance abuse disorders. A few clinically significant false-positive results have been reported with these two medications. The buprenorphine assay is subject to cross-reactivity from the synthetic opioid tramadol (
      • Shaikh S.
      • Hull M.J.
      • Bishop K.A.
      • Griggs D.A.
      • Long W.H.
      • Nixon A.L.
      • Flood J.G.
      Effect of tramadol use on three-point-of-care and instrument based immunoassay for urine buprenorphine.
      ). Quetiapine use has been reported to cause a false-positive methadone screening test (
      • Cherwinski K.
      • Petti T.A.
      • Jekelis A.
      False methadone-positive urine drug screens in patients treated with quetiapine.
      ).

      MAINTAINING PATIENT CONFIDENTIALITY IN CHILDREN AND ADOLESCENTS

      The ASAM and the AAP recommend that adolescents are involved in their care and that clinicians obtain informed consent before performing UDS (
      • Jarvis M.
      • Williams J.
      • Hurford M.
      • Lindsay D.
      • Lincoln P
      • Giles L.
      • Safarian T.
      Appropriate use of drug testing in clinical addiction medicine.
      ). If a patient presents acutely ill and in imminent danger, UDS should be performed before obtaining consent. The clinician and adolescent should have an open discussion regarding privacy and clarify permission to share results with a parent or guardian (
      • Jarvis M.
      • Williams J.
      • Hurford M.
      • Lindsay D.
      • Lincoln P
      • Giles L.
      • Safarian T.
      Appropriate use of drug testing in clinical addiction medicine.
      ). If the patient does not want UDS results shared, the clinician must respect the adolescents’ wishes but should also encourage them to share the results with their parent/guardian. Although there are scenarios in which clinicians can maintain patient confidentiality, this is not always the case. If a clinician suspects the substance use puts the patient in imminent danger, there are legal and ethical implications, and the clinician may need to disclose information to a parent or guardian (
      • Jarvis M.
      • Williams J.
      • Hurford M.
      • Lindsay D.
      • Lincoln P
      • Giles L.
      • Safarian T.
      Appropriate use of drug testing in clinical addiction medicine.
      ). If substance use is suspected and the adolescent refuses the screening, the refusal should be documented, and the adolescent should be referred to an addiction or mental health specialist (
      • Levy S.
      • Siqueira L.M.
      • Ammerman S.D.
      • Gonzalez P.K.
      • Ryan S.A.
      • Smith V.C.
      Committee on Substance Abuse
      Testing for drugs of abuse in children and adolescents.
      ).

      POSITIVE RESULTS

      If an immunoassay is the initial UDS modality and the positive result is unexpected, confirmatory GC-MS should be performed. The clinician should also attempt to have an honest discussion with the patient regarding the test results, in hopes that the patient may provide additional information, such as substances that were not detected on the panel (
      • Levy S.
      • Siqueira L.M.
      • Ammerman S.D.
      • Gonzalez P.K.
      • Ryan S.A.
      • Smith V.C.
      Committee on Substance Abuse
      Testing for drugs of abuse in children and adolescents.
      ). If a true-positive result is confirmed and matches the adolescent's reporting, the clinician should begin developing a treatment plan. A treatment plan may include abstinence, ongoing testing, and/or referral to a treatment center (
      • Levy S.
      • Siqueira L.M.
      • Ammerman S.D.
      • Gonzalez P.K.
      • Ryan S.A.
      • Smith V.C.
      Committee on Substance Abuse
      Testing for drugs of abuse in children and adolescents.
      ). In most states, adolescents can consent to substance abuse treatment without a parent or guardian (
      • Levy S.
      • Siqueira L.M.
      • Ammerman S.D.
      • Gonzalez P.K.
      • Ryan S.A.
      • Smith V.C.
      Committee on Substance Abuse
      Testing for drugs of abuse in children and adolescents.
      ). If the patient denies substance use despite the positive result and no alternative explanation exists, results should still be discussed with the adolescent. Repeat drug testing may be valuable if suspicion remains high for substance abuse.

      CONCLUSION

      When using UDS as a tool to make clinical decisions about high-risk medications, it is important to understand the differences between UDS testing modalities (immunoassay vs. GC-MS), common causes of false-positive or false-negative results, and the detection window of specific medications. Remember that drug interferences may vary on the basis of the immunoassay used and that new drug interferences are discovered annually. If ever in doubt, if there is a possible drug interference with an immunoassay, call the laboratory that performed the test and ask about known drug interferences. Send a confirmatory GC-MS test before making any decisions about the patient if there is no known interference with any of the patient's medications.

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      Biography

      Logan Johnson Doriety, Post Graduate Year - 2 Pharmacist Resident, Department of Pharmacy, New Hanover Regional Medical Center, Wilmington, NC.
      Elizabeth Anne Farrington, Clinical Pharmacist, Pediatrics, Department of Pharmacy, New Hanover Regional Medical Center, Wilmington, NC.