Interpretation of Pain Management Testing Results Using Case Examples

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1 Interpretation of Pain Management Testing Results Using Case Examples Philip M. Sobolesky, 1 * Breland E. Smith, 1 Amadeo J. Pesce, 2 and Robert L. Fitzgerald 1 Background: Because of the increasing volume of opiate-related overdoses, clinical testing of urine for drugs and related compounds in pain management clinics has become increasingly important. Interpreting findings of drugs present in urine specimens requires knowledge of pharmacokinetics, metabolism, drug purity, and cutoff concentrations used to report a positive result. Content: This case-based mini-review provides examples of how to interpret immunoassay and quantitative confirmatory urine drug-testing results. Particular emphasis is placed on interpretation of opiate and benzodiazepine results, as these drugs have complicated metabolic profiles. Summary: Both determining patient medication compliance and identifying the presence of additional drugs provides important information to the treating physician involved in managing pain. Mass spectrometry-based methods are required to identify specific drugs present and can provide important quantitative data for interpreting opiate medication compliance. IMPACT STATEMENT Patient care providers will benefit from a concise case-based mini-review of common drugs identified in urine specimens. The cases presented illustrate decisions that testing laboratories regularly encounter when providing interpretation. This article aims to inform those involved in interpreting urine drug-testing results about the influence of pharmacokinetics, cutoff concentrations, hydrolysis status, metabolism, acceptable limits of drug impurities, and specimen adulteration when monitoring patient compliance. BACKGROUND In 2014, million persons in the US were prescribed long-term opioid therapy (1). Urine drug testing (UDT) 3 is the recommended tool for monitoring patient compliance of prescribed controlled substances (2, 3). Many patients treated for pain management will sign a contract with their 1 Department of Pathology, Center for Advanced Laboratory Medicine, University of California, San Diego Health Systems, San Diego, CA; 2 Precision Diagnostics, San Diego, CA. *Address correspondence to this author at: Department of Pathology, Center for Advanced Laboratory Medicine, University of California, San Diego Health Systems, San Diego, CA. Fax ; psobolesky@ucsd.edu. DOI: /jalm American Association for Clinical Chemistry 3 Nonstandard abbreviations: UDT, urine drug testing; IA, immunoassay; USP, United States Pharmacopeia; EDDP, 2-ethylidene-1,5-dimethyl- 3,3-diphenylpyrrolidine; EtG, ethyl glucuronide; EtS, ethyl sulfate; 6-MAM, 6-monoacetyl morphine; MAMP, methamphetamine; THC-COOH, carboxy-δ 9 -tetrahydrocannabinol. January : JALM 1 Copyright 2017 by American Association for Clinical Chemistry.

2 physician agreeing to UDT with the understood intent of monitoring compliance. Current UDT guidelines recommend the use of immunoassay (IA) screens followed by a more specific technique such as LC-MS/MS for drug confirmation (4). Numerous limitations regarding high false-negative rates with IA screening have been demonstrated in patients treated for chronic pain (5, 6). A retrospective analysis found that IA had <80% sensitivity compared with LC-MS/MS for opiates, benzodiazepines, amphetamines, cocaine, and buprenorphine with only oxycodone detected in 92.5% of positive samples (7). UDT IAs are subject to falsepositive results, interferences, and deficiencies having been extensively reviewed in the literature (5, 6, 8). Despite the known inferiority of IA compared with LC-MS/MS testing, current government and private payment models do not support the use of only LC-MS/MS testing for all patients (9). The purpose of this review is to describe how patient medication compliance is evaluated using a case-based approach. To interpret drug-testing results, one must understand drug metabolism, medication impurities, the usual expected drug concentrations, the cutoff concentration of the testing method, and if specimens were hydrolyzed prior to analysis. Common pathways of metabolism for opiates and benzodiazepines are shown in Figs. 1 and 2, respectively, because several drugs share common metabolites. The cases presented cover various scenarios and include both qualitative IA and confirmatory testing results. These cases highlight the importance of quantitative drug monitoring to identify the presence of prescribed and nonprescribed drugs. Because the focus of this review is on quantitative drug result interpretations, rather than IA deficiencies, please refer to the following review for information on common interferences of UDT IA (8). Understanding the importance of allowable impurities of United States Pharmacopeia (USP) opioid preparations is also necessary because impurities of the pharmaceutical preparations can be identified when patients are prescribed large doses of opiates for pain management. Table 1 is a list of the manufacturing impurities for USP opiates that could be identified in high-dosage compliant patients. It is also important to understand if the confirmatory method includes hydrolysis. In this review all specimens were hydrolyzed with β-glucuronidase prior to LC-MS/MS analysis. Validity testing for the specimens presented in these cases followed similar recommendations set by the World Health Organization and the US federal workplace drug-testing program, such that creatinine must be 20 mg/dl, oxidant <200, ph between 4.7 and 7.8, a specific gravity between and 1.035, and a normal physiological temperature (4, 10). Unless otherwise noted, the specimens passed validity testing. The drug concentrations in each case (Table 2) are expressed in nanograms per milliliter. Creatinine correction or normalization refers to the reporting of urine analyte levels as a ratio to urine creatinine concentration and is used to adjust measured urine analyte levels to hydration status (11, 12). This approach has some limitations in that this may not be accurate for those with impaired kidney function or other conditions leading to variable creatinine clearance, but it is useful in certain applications, such as monitoring terminal excretion of compounds with long biological half-lives. Urine specimen adulteration Adulteration of a urine specimen refers to any attempt by patients to modify their urine contents to pass or cheat a drug test. One method of urine adulteration is to substitute one's urine with purchased synthetic urine or a drug-free urine sample from another person. Synthetic urine is manufactured with similar ph, creatinine, and salt levels to normal urine, and can contain unique compounds like benzisothiazolinone and ethylene glycols (13). Another common approach to beating a urine drug test involves attempting to flush 2 JALM :04 January 2018

3 Fig. 1. Opiate drugs and common metabolites observed after hydrolysis in urine. Heroin is metabolized to 6-acetylmorphine, which can be metabolized to morphine and then hydromorphone (A). Codeine can metabolize to morphine, hydrocodone, and norhydrocodone. Methadone metabolizes to EDDP (B). Buprenorphine is metabolized to norbuprenorphine (C). Fentanyl is metabolized to norfentanyl (D). Oxycodone can be converted into oxymorphone and noroxycodone (E). January : JALM 3

4 Fig. 2. Benzodiazepine drugs and common metabolites observed after hydrolysis. Alprazolam is metabolized to α-hydroxyalprazolam (A). Clonazepam is metabolized into 7-aminoclonazepam (B).For patients prescribed chlordiazepoxide, medazepam, clorazepate, halazepam, or diazepam, positive confirmations would include the parent drug and nordiazepam and oxazepam (C). Diazepam can also metabolize to temazepam and then to nordiazepam and oxazepam. out the drugs and/or dilute the urine via ingestion of commercially available fluids or tablets taken with excess water. These include detoxifying agents and diuretics, of which there exists a plethora available online for purchase (14). Lastly, addition of chemicals or substances that interfere with testing is also common practice. This includes, but is not limited to, oxidants that oxidize and destroy compounds in urine and chromogens that interfere with spectrophotometric detection, such as bleach, peroxides, pyridinium chlorochromate, nitrites, and halogens (bromine or iodine) (14). Assays have been developed to detect the presence of most adulterants. Data for all the cases are summarized in Table 2. Each sample was first tested by IA based on the physician order. Samples with positive IA results 4 JALM :04 January 2018

5 Table 1. USP manufacturing impurities (w/w) allowable limits. Formulation Process impurities Allowable limit, % Codeine Morphine 0.15 Hydrocodone Codeine 0.15 Hydromorphone Morphine 0.15 Hydrocodone 0.1 Morphine Codeine 0.5 Oxycodone Hydrocodone 1.0 Oxymorphone Hydromorphone 0.15 Oxycodone 0.5 are reflexed for LC-MS/MS confirmation of >60 prescription and illicit substances. Below is a detailed interpretation for each of the cases that were selected to show commonly encountered scenarios for which interpretation is not straightforward. Case 1: The patient was prescribed Lyrica (pregabalin), MS Contin (extended-release morphine), oxycodone, Ritalin (methylphenidate), and Xanax (alprazolam). The sample was IA positive for benzodiazepines, opiates, and oxycodone (see Table 1 in the Data Supplement that accompanies the online version of this article at content/vol2/issue4 for IA cutoff values). The expected LC-MS/MS-positive results for this patient were morphine ( ng/ml) and its metabolite hydromorphone (733 ng/ml), consistent with the prescribed medication MS Contin. Oxycodone (5470 ng/ml) and its metabolites oxymorphone (1220 ng/ml) and noroxycodone (15700 ng/ml) were consistent with the prescribed medication oxycodone (Table 2). The findings were negative for α-hydroxyalprazolam and alprazolam by LC-MS/MS (cutoff concentration = 50 ng/ml), suggesting no recent intake of prescribed Xanax. The LC-MS/MS assay used does not monitor methylphenidate or pregabalin. The patient was also positive for the nonprescribed opioids hydrocodone (7 ng/ml) and its metabolite norhydrocodone (20 ng/ml), codeine (70 ng/ml), fentanyl (18 ng/ml), its metabolite norfentanyl (238 ng/ml), as well as the benzodiazepines nordiazepam (906 ng/ml), oxazepam (943 ng/ml), temazepam (1970 ng/ml), and clonazepam (16 ng/ml) and its metabolite 7-aminoclonazepam (1520 ng/ml). Because the patient in case 1 was prescribed morphine, it is expected that morphine and its related metabolite hydromorphone (see Fig. 1) would be present. Hydromorphone is a minor metabolite of morphine (ratio range for hydromorphone to morphine = ) and is generally detected at concentrations significantly less than the parent compound for patients taking morphine (15). The presence of hydrocodone cannot be attributed to metabolism and may be the result of manufacturing impurities (16). There is an allowable limit of 1.0% hydrocodone impurity (Table 1) in USP oxycodone. The low amounts of hydrocodone and its metabolite norhydrocodone are consistent with a compliant patient prescribed oxycodone that has a small amount of hydrocodone as a pharmaceutical impurity. Similarly, the low concentration of codeine could be the result of the MS Contin containing up to 0.5% codeine as a pharmaceutical impurity (17). Having the quantitative results for the opiates is important in this case because the concentration of hydromorphone, hydrocodone, and codeine are interpretable based on metabolism and known impurities. Without the quantitative results, interpretation of these findings would be more difficult and less informative to the treating physician. The fentanyl and norfentanyl present in this patient's urine are not allowable impurities in any prescribed medications; therefore, their detection is an indication of fentanyl use. From the known metabolism of commonly prescribed benzodiazepines (see Fig. 2), it is clear that the benzodiazepines detected in this patient's urine are not consistent with the prescribed medications. The presence of the unexpected benzodiazepines and fentanyl, combined with the absence of the alprazolam, suggests non- January : JALM 5

6 Table 2. Overview of cases including patient prescribed medications and quantitative LC-MS/MS UDT results. Consistent results Inconsistent results Case Prescribed medications Prescribed medications detected Prescribed medications not Detected drug/medication not prescribed Compound ng/ml detected Compound ng/ml 1 Lyrica Hydrocodone 7 Norhydrocodone 20 Codeine 70 MS Contin Hydromorphone 733 Fentanyl 18 Morphine Norfentanyl 238 Oxycodone Oxycodone Aminoclonazepam 1520 Oxymorphone 1220 Clonazepam 16 Noroxycodone Nordiazepam 906 Ritalin Oxazepam 943 Xanax α-hydroxyalprazolam Temazepam Alprazolam α-hydroxyalprazolam 22 Alprazolam 16 MS Contin Hydromorphone 74 Hydrocodone 15 Morphine 4990 Norhydrocodone 26 Oxycodone Oxycodone 6910 Oxymorphone 1150 Noroxycodone Suboxone Buprenorphine 15 None found Cocaine metabolite Norbuprenorphine 20 Naloxone Neg 4 Suboxone Buprenorphine 7460 Norbuprenorphine Cocaine metabolite 170 Naloxone None Buprenorphine 305 Norbuprenorphine 1200 Methadone 1430 Cotinine Ambien Ambien EtG 1070 Diazepam Nordiazepam 61 Oxazepam 314 EtS 503 Temazepam Suboxone Buprenorphine MAM 32 Norbuprenorphine 235 Benzoylecgonine 5 Naloxone Ethyl alcohol 30 a 8 None Morphine 6560 Hydromorphone 93 Codeine 244 α-hydroxyalprazolam 85 Amphetamine 1550 Methamphetamine Continued on page xxx 6 JALM :04 January 2018

7 Table 2. Overview of cases including patient prescribed medications and quantitative LC-MS/MS UDT results. (Continued from page xxx) Consistent results Inconsistent results Prescribed medications Detected drug/medication detected Prescribed not prescribed Case Prescribed medications Compound ng/ml medications not detected Compound ng/ml 9 None THC-COOH (day 0) 2230 THC-COOH (day 4) 2880 THC-COOH (day 13) 1870 THC-COOH (day 25) 1510 THC-COOH (day 34) 94 THC-COOH (day 46) None Oxazepam 29 Benzoylecgonine 18 Dextromethorphan 228 Dextrorphan 2810 a Denotes concentration units of mg/dl. compliance and warrants a discussion with the patient (18). Case 2: This patient was prescribed alprazolam, MS Contin, and oxycodone. The IA results were positive for opiates and oxycodone but negative for benzodiazepines. Consistent with this patient's prescriptions, positive confirmatory results included α-hydroxyalprazolam (22 ng/ml), alprazolam (16 ng/ml), hydromorphone (74 ng/ml), morphine (4990 ng/ml), oxycodone (6910 ng/ml), oxymorphone (1150 ng/ml), and noroxycodone (9950 ng/ml). The patient was also positive for hydrocodone (15 ng/ml) and norhydrocodone (26 ng/ml). Because the allowable limit for hydrocodone in oxycodone manufacturing is 1.0% (Table 1), the detectable level of hydrocodone is consistent with a pharmaceutical impurity of the prescribed oxycodone. The negative IA for benzodiazepines illustrates the value of tandem mass spectrometry over IA in the detection of true-positive findings (19). As shown in Table 1 of the online Data Supplement, alprazolam must be present at 219 ng/ml to trigger a positive IA, and in this case only 16 ng/ml was present. It is also important to consider metabolism and excretion of the parent compounds. In the case of alprazolam, approximately 20% of the dose is excreted in urine as the parent drug (20); therefore, looking for the parent drug and a primary metabolite in urine is reasonable. For some benzodiazepines, such as lorazepam, negligible amounts of the parent drug are excreted in urine, so it is essential that the correct metabolites are targeted by both screening and confirmatory techniques (21). Case 3: This patient was prescribed suboxone, a combination drug formulation containing buprenorphine and naloxone in a 4:1 (g/g) ratio, respectively. The specimen screened positive for buprenorphine and cocaine metabolite. The specimen contained buprenorphine (15 ng/ml) and norbuprenorphine metabolite (20 ng/ml). Naloxone was reported as negative. Typically, these low concentrations of buprenorphine and norbuprenorphine are accompanied by similarly low concentrations of naloxone. However, the LC- MS/MS cutoff for a positive naloxone finding is 100 ng/ml; thus, the presence of naloxone was likely below the cutoff value and was reported as negative. This is another example where the cutoff concentration, the minimum value for a report- January : JALM 7

8 able positive result, must be considered before categorizing the result as consistent or inconsistent with prescribed medications. The positive cocaine metabolite (benzoylecgonine of ng/ml) can be interpreted as illicit drug use and patient noncompliance. Case 4: This patient was prescribed suboxone. The specimen was positive by IA for buprenorphine and negative for all other drugs. Positive confirmatory drug identifications were buprenorphine (7460 ng/ml), naloxone (2030 ng/ml), and cocaine metabolite (170 ng/ml). However, norbuprenorphine, the major metabolite of buprenorphine, was not detected. For patients prescribed suboxone, it is expected that a metabolite-toparent drug ratio of about 4.52 (3.97) will be observed (22). Because the detected levels of buprenorphine and naloxone were about 4:1 and no metabolites were present, the most likely interpretation of these results is that the patient supplemented (also known as spiked ) his urine with suboxone. This means that a small amount of suboxone was added directly to the urine specimen to appear compliant. In addition, this patient was positive for benzoylecgonine by tandem mass spectrometry (cutoff of 50 ng/ml), indicating use of cocaine (23). The LC-MS/MS benzoylecgonine result (170 ng/ml) seems to contradict the negative IA cocaine metabolite result, but in fact these results are in concordance because the cutoff for a positive cocaine metabolite IA screen is 300 ng/ml. This is a good example of where commonly used immunoassay cutoff concentrations can yield falsenegative results in this patient population. Case 5: No prescriptions were listed for this patient, and there were no signs of specimen adulteration. Failure to list prescribed medication is common, making interpretation of UDT results difficult for the laboratory. The specimen screened positive by IA for buprenorphine and methadone. The patient had detectable levels of buprenorphine (305 ng/ml), norbuprenorphine (1200 ng/ ml), and methadone (1430 ng/ml). Over the span of 35 days, this patient provided 6 urine specimens, 4 of which tested positive for these drugs at similar levels, with 2 of these specimens containing only buprenorphine, norbuprenorphine, and cotinine. The major issue in this case is that the urine was consistently negative for 2-ethylidene-1,5- dimethyl-3,3-diphenylpyrrolidine (EDDP), a methadone metabolite (see Fig. 1B), while being positive for methadone on the 4 occasions previously described. For patients taking methadone, a ratio of methadone to EDDP of about 1:1 is expected (24, 25). The high concentration of methadone accompanied by the lack of detectable levels of EDDP indicates that methadone was spiked directly into the urine specimen. A likely interpretation of these results is that the patient was prescribed suboxone for which he/she appears to be compliant, but also spiked the urine with methadone for reasons that are not clear. The positive cotinine result indicates that this subject took nicotine, which could have come from smoking or ingesting some other tobacco product. Specimen validity Case 6: This patient was prescribed Ambien (zolpidem) and Valium (diazepam). The IA results were positive for benzodiazepines. Expected positive results included the diazepam metabolites nordiazepam (61 ng/ml), oxazepam (314 ng/ml), and temazepam (365 ng/ml). However, the specimen was negative for zolpidem and positive for ethyl glucuronide (EtG) (1070 ng/ml), ethyl sulfate (EtS) (503 ng/ml), and cotinine (2260 ng/ml). EtG and EtS are metabolites of ethanol, and their presence can be detected for up to 5 days after alcohol consumption (26). Assays for these metabolites are typically designed with a cutoff for a positive result of 500 ng/ml to exclude the potential for falsepositive results resulting from use of alcoholic mouthwash and hand sanitizers (26). The specimen had a creatinine concentration of 16 mg/dl (reference, >20) with no oxidants, a ph of 6.7 (reference, ), and a specific gravity of JALM :04 January 2018

9 (reference, ). The low creatinine and specific gravity together indicate dilute urine, suggesting the patient had consumed large quantities of water before providing a urine specimen. It is common practice for physicians who treat patients on a pain management regimen to prohibit ethanol ingestion and require the patient to contractually agree to regular UDT. Impetus for self-inducing an aqueous diuresis in this patient could be ethanol ingestion (as evidenced by the positive EtG and EtS results). In this case, consumption of large volumes of fluid was not sufficient to reduce urine concentrations of ethanol metabolites below the limit of detection. Case 7: This patient was prescribed suboxone and screened positive by IA for buprenorphine but negative for other drugs. Quantitative testing was positive for buprenorphine (31800 ng/ml), norbuprenorphine (235 ng/ml), and naloxone (13300 ng/ml). Additional positive results included 6-monoacetyl morphine [(6-MAM) 32 ng/ml], benzoylecgonine (5 ng/ml), and ethanol (30 mg/dl). The specimen had a within-range creatinine level and specific gravity, with no oxidant detected. However, the ph was 9.8 (reference range, ), indicating the sample had been adulterated. Similar to case 5, this patient sample had a buprenorphine-to-naloxone ratio of 4:1 with low levels of norbuprenorphine, suggesting that this patient had taken suboxone within the past 24 h but nonetheless decided to spike the specimen with his prescription to appear compliant. A ph >2.0 U outside of the reference range, an abnormal ratio of buprenorphine to norbuprenorphine, and the detection of illicit drugs strongly suggest a noncompliant patient. Moreover, the presence of significant quantities of ethanol without its metabolites EtG or EtS, coupled with a high ph, could also be consistent with the formation of ethanol by microbial fermentation, which means the urine may have not been a fresh sample. A urine sample that has been allowed to sit at room temperature for days is subject to yeast and bacterial growth, both of which can produce ethanol (27). It is possible that the patient obtained a urine sample from a presumed negative individual, and the sample was stored before the patient spiked it with suboxone. An alternative explanation is that the patient added an ethanol-containing adulterant; however, this would not necessarily explain the excessively high ph. The finding of 6-MAM, a specific indicator of heroin use, in the absence of morphine is highly unusual because it is usually found along with high concentrations of morphine (28). This patient had a history of heroin use as evidenced by previous specimens positive for 6-MAM and morphine (data not shown). The most likely explanation for the low levels of 6-MAM detected would be that this patient used a small quantity of heroin within 2hoftesting (28), thus giving enough time to metabolize heroin to 6-MAM but not enough time to accumulate a detectable amount of morphine (29). The presence of 6-MAM irrespective of morphine is considered proof of heroin or 6-MAM intake (30, 31). Differentiating medicinal from illicit use in positive methamphetamine result Case 8: This patient had no reported prescriptions, and the specimen had no signs of adulteration. The specimen screened positive for opiates and amphetamines and was negative for benzodiazepines. The following drugs were identified: morphine (6560 ng/ml), hydromorphone (93 ng/ml), codeine (244 ng/ml), α- hydroxyalprazolam (85 ng/ml), amphetamine (1550 ng/ml), and methamphetamine (12400 ng/ml), of which 99% was the d-isomer. In the absence of a prescription for morphine, the opiates quantified in this case are most consistent with the use of heroin. 6-MAM has a half-life of about 10 to 40 min and often is not detected when urine specimens are collected from heroin users (32). The most likely interpretation is that the morphine is a metabolite of heroin, and the January : JALM 9

10 hydromorphone is a metabolite of morphine. Codeine is not a metabolite of morphine but is frequently detected in heroin users because the heroin is contaminated with acetylcodeine (33, 34). The presence of codeine and morphine could be expected if the patient had been prescribed codeine, but in this case the high concentration of morphine relative to the amount of codeine makes it less likely. The methamphetamine (MAMP) d-isomer is a powerful central nervous system stimulant associated with illicit drug use but could be present in patients taking desoxyn or benzphetamine (35, 36). Prescriptions for these medications are rare. The l- isomer is primarily used as a vasoconstrictor commonly found in Vicks Inhaler as a nasal decongestant (37). Federal workplace drug-testing programs have established that a chiral result of <20% d-mamp (or >80% l-mamp) indicates the use of Vicks Inhaler or selegiline, whereas the reverse indicates use of d-mamp or a compound that metabolized to d-mamp (4, 38). In this case, we can rule out the use of a Vicks Inhaler because of the detection of <1% l-mamp. Because no patient medications were provided, no conclusive statements can be made regarding illicit drug use; however, this is the most likely explanation. Determining patient abstinence from marijuana smoking Case 9: The patient had no known prescription medications, and none of the specimens displayed signs of adulteration. The patient was tested 6 times over 46 days and screened positive for the cannabis metabolite carboxy-δ 9 -tetrahydrocannabinol (THC-COOH) the first 4 visits. The quantitative values at the start were 2230 ng/ml, 2880 ng/ml (4 days later), 1870 ng/ml (13 days later), 1510 ng/ml (25 days later), 94 ng/ml (34 days later), and 16 ng/ml (46 days later). Bergamaschi et al. have shown 10 of 11 chronic frequent cannabis smokers were >0.25 ng/ml for THC-COOH after 30 days of sustained abstinence (39). The patient values suggest no additional use of cannabis after the fourth visit. Creatinine-corrected concentrations of oxazepam Case 10: This patient had no reported prescriptions, and the specimen had no signs of adulteration. The specimen had no positive screening results. The following drugs were identified: oxazepam (29 ng/ml), benzoylecgonine (18 ng/ml), dextromethorphan (228 ng/ml), and its metabolite dextrorphan (2810 ng/ml). This patient had been tested on 6 different visits over a 1-month period, and the measured oxazepam concentrations (ng/ml) were 230, 156, 50, 26, 33, and 29, respectively (see Fig. 1 in the online Data Supplement). The corresponding creatinine-corrected results for oxazepam (ng/mg creatinine) were 150, 69, 63, 45, 26, and 18. This illustrates 2 points: First, it demonstrates the lengthy detection window of oxazepam. Second, it also shows that creatininecorrected concentrations continue to decline, whereas the measured concentration (ng/ml) bumps up at the fifth visit. This increased value could suggest reuse when in fact the patient was just less hydrated than at the previous visit. Creatinine levels are known to be affected by a number of biological factors (40); therefore, caution is advised when using creatinine-corrected drug concentrations to interpret compliance. SUMMARY This review article used 10 cases from a pain management testing facility to highlight a few of the common drug-testing scenarios that may be encountered. Appropriate interpretation of UDT results is vital for a variety of clinical and social programs. Table 2 in the online Data Supplement provides a list of comments that can be used to aid in interpreting positive UDT drug findings. These cases demonstrate the impor JALM :04 January 2018

11 tance of several factors when interpreting a positive result, including the effect of impurities in pharmaceutical preparations, the cutoff concentration for a positive result, the common metabolic pathways, the effect of normalizing relative to creatinine concentration, and the relative concentration of metabolites to parent drug. Specimen validity must also be considered during the interpretation process to ensure the patient did not dilute or adulterate the sample. For lipophilic drugs, such as oxazepam and THC metabolites, it is important to comprehend the role that body burden can play in the length of time drugs can be detected in urine. Patients taking these drugs can test positive for weeks after abstention. These cases highlight some of the challenges associated with interpreting UDT results. Whenever results are not clear, providers should consult with a laboratory professional familiar with this kind of testing. Author Contributions: All authors confirmed they have contributed to the intellectual content of this paper and have met the following 4 requirements: (a) significant contributions to the conception and design, acquisition of data, or analysis and interpretation of data; (b) drafting or revising the article for intellectual content; (c) final approval of the published article; and (d) agreement to be accountable for all aspects of the article thus ensuring that questions related to the accuracy or integrity of any part of the article are appropriately investigated and resolved. Authors Disclosures or Potential Conflicts of Interest: Upon manuscript submission, all authors completed the author disclosure form. Employment or Leadership: A.J. Pesce, Precision Diagnostics LLC. Consultant or Advisory Role: None declared. Stock Ownership: None declared. Honoraria: None declared. Research Funding: None declared. Expert Testimony: None declared. Patents: None declared. Acknowledgments: The authors thank Megan Demers for assistance in identifying these cases. REFERENCES 1. Volkow ND, McLellan AT. Opioid abuse in chronic pain misconceptions and mitigation strategies. N Engl J Med 2016;374: Manchikanti L, Atluri S, Trescot AM, Giordano J. Monitoring opioid adherence in chronic pain patients: tools, techniques, and utility. Pain Physician 2008;11:S Magnani B, Kwong T. Urine drug testing for pain management. Clin Lab Med 2012;32: Mandatory guidelines for federal workplace drug testing programs. Department of Health and Human Services. (Accessed July 2017). 5. Darragh A, Snyder ML, Ptolemy AS, Melanson S. KIMS, CEDIA, AND HS-CEDIA immunoassays are inadequately sensitive for detection of benzodiazepines in urine from patients treated for chronic pain. Pain Physician 2014;17: Pesce A, Rosenthal M, West R, West C, Crews B, Mikel C, et al. An evaluation of the diagnostic accuracy of liquid chromatography tandem mass spectrometry versus immunoassay drug testing in pain patients. Pain Physician 2010;13: Snyder ML, Fantz CR, Melanson S. Immunoassay-based drug tests are inadequately sensitive for medication compliance monitoring in patients treated for chronic pain. Pain Physician 2017;20:SE1 SE9. 8. Saitman A, Park HD, Fitzgerald RL. False-positive interferences of common urine drug screen immunoassays: a review. J Anal Toxicol 2014;38: Local coverage determination (LCD): controlled substance monitoring and drugs of abuse testing (L35724). Center for Medicare & Medicaid Services. details/lcd-details.aspx?lcdid=35724&contrid= 380&ver=35&ContrVer=1&CntrctrSelected= 380*1&Cntrctr=380&DocType=Active&s=All&bc= AggAAAQAAAAAAA%3d%3d& (Accessed July 2017). 10. Biological monitoring of chemical exposure in the workplace: guidelines. Geneva: World Health Organization (Accessed July 2017). 11. Cone EJ, Caplan YH, Moser F, Robert T, Shelby MK, Black DL. Normalization of urinary drug concentrations with specific gravity and creatinine. J Anal Toxicol 2009;33: Barr DB, Wilder LC, Caudill SP, Gonzalez AJ, Needham LL, Pirkle JL. Urinary creatinine concentrations in the U.S. population: implications for urinary biologic monitoring measurements. Environ Health Perspect 2005;113: Goggin MM, Tann CM, Miller A, Nguyen A, Janis GC. Catching fakes: new markers of urine sample validity and invalidity. J Anal Toxicol 2017;41: Dasgupta A. The effects of adulterants and selected.. January : JALM 11

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