Advance Urine Toxicology Testing Article

Journal of Addictive Diseases, 29:436–448, 2010Copyright c© Taylor & Francis Group, LLCISSN: 1055-0887 print / 1545-0848 onlineDOI: 10.1080/10550887.2010.509277

Advanced Urine Toxicology Testing

Peter L. Tenore, MD, FASAM

ABSTRACT. Urine toxicology screening testing is an important standard of care in the addiction andpain treatment setting, offering a reproducible, unbiased, and accurate laboratory test to monitor patientsand provide objective support for clinical observations. It has been shown that physicians do not haveproficiency in the ordering or interpretation of these tests. This article is an attempt to respond to thatneed. Current antibody-based enzymatic immunoassays (EIAs) used for urine toxicology screeningare useful to detect classes of drugs (ex., opiate) but cannot determine which specific drug (ex.,morphine) is present. Gas chromatography and mass spectroscopy can determine exactly which drugsare present, allowing prescribed (or illicit) opiates and benzodiazepines to be identified. This articlewill discuss principles and details of opiate and benzodiazepine EIA and gas chromatography and massspectroscopy urine toxicology testing. The approach to detecting patients attributing positive opiateEIAs to prescription opiates who are using heroin or other opioids will be reviewed. Cases of controlledprescription drugs that do not produce the expected positive urine tests (ex., oxycodone producingnegative opiate screening tests) will be discussed. How to differentiate codeine from heroin and therole of poppy seeds in toxicology will be examined. The case of an anti-depressant drug that producesfalse-positive benzodiazepine results and antibiotics that cause positive opiate urine toxicology resultswill be reviewed. Common benzodiazepines (ex., clonazepam and lorazepam) that do not reliablyproduce positive benzodiazepine EIAs will be discussed. The approach to detection and managementof all these types of toxicology cases will be reviewed, and it is hoped that the analyses presented willimpart an adequate information base to medical providers and staff members of drug treatment and paincenters, enabling them to order and interpret these tests in the clinic more effectively as an integratedpart of whole patient care.

KEYWORDS. Gas chromatography, mass spectroscopy, urine toxicology, opiate, benzodiazepine,morphine, codeine, EIA, ELISA, EMIT, fluoroquinolone, sertraline, drug screening, lorazepam,clonazepam

INTRODUCTION

Rational for Drug Monitoring

Three basic reasons are used to consider urinedrug monitoring in patients who are in drug treat-ment or who are prescribed opioids or benzodi-azepines.The first reason is to reassure medicalproviders that the patients who are prescribedopioids and benzodiazepines are taking medi-

Peter L. Tenore is affiliated with Albert Einstein College of Medicine, Bronx, NY.Address correspondence to: Peter L. Tenore, MD, FASAM, Wellness Center at Waters Place, 1510 Waters

Place, Bronx, NY 10461 (E-mail: [email protected]).

cation as directed, evidenced by positive resultsin urine drug testing.1−3 The second reason isthat urine drug testing is used to detect pos-sible diversion of medication (i.e., stockpilingor selling of controlled prescribed substancesto unauthorized others), evidenced by negativeurine drug tests. The overdose mortality ratein the United States due to diverted prescribedopioid analgesics as reported on death certifi-cates increased dramatically (by 91.2%) from

Peter L. Tenore 437

1999 to 2002, indicating that “a national epi-demic of drug poisoning deaths began in the1990’s and prescriptions for opioid analgesicscontributed to the increases in drug poison-ing deaths.”4 The most common opioids im-plicated in overdose deaths were, in order offrequency of occurrence, methadone, fentanyl,oxycodone, hydromorphone, hydrocodone, andmorphine and were obtained by overdose vic-tims illegally from patients with legitimate pre-scriptions; therefore, it is critical for providersto ensure that patients prescribed these medi-cations are taking and not diverting them.4 Inaddition to patient history and clinical presen-tation, random urine drug testing is an essentialand objective part of this monitoring process.1,2,5

The third reason is to detect the presence ofillicit non-prescribed drugs, such as heroin,cocaine, methamphetamine, phencyclidine, non-prescribed opioids, and non-prescribed benzodi-azepines, according to community prevalences,the presence of which suggests that patients maynot be entirely responsible to manage prescribedopioids and benzodiazepines and need furthertherapeutic intervention.1,3,6

The discussion in this article will be limitedto discussing two common classes of drugs thatare widely abused and are widely prescribed byphysicians and other medical providers: benzo-diazepines and opioids. How urine drug testingcan be used to differentiate prescribed versus il-licit drugs of these classes and to contribute tothe medical and psychosocial care of these pa-tients will be reviewed.

Enzyme-Immuno-Assay Testing

The most common drug screening tech-niques are antibody-based, enzyme-mediatedimmunoassays. These are inexpensive, auto-mated, rapid, and accurate.1 Various tests suchas Enzymatic Immunoassay (EIA), Enzyme Me-diated Immunoassay Technique (EMIT), En-zyme Linked Immunosorbent Assay (ELISA),and Cloned Enzyme Donor Immuno-Assay (CE-DIA) refer to the same basic process: a spe-cific anti-drug antibody is added to the patient’surine and, if the specific drug is present, theantibody binds to the drug, enabling a measur-able indicator reaction to occur that is reported

as “positive.”7 For simplicity, in this article, theterm enzymatic immunoassay (EIA) will be usedto represent all these antibody-mediated urinetoxicology tests.

The opiate EIA uses an anti-morphine anti-body to detect opiates; and the BenzodiazepamEIA uses an anti-diazepam antibody to detectbenzodiazepines.8 Because these antibodies arespecific to morphine and diazepam, there willbe both false-negative and false-positive re-sults with non-morphine opioids (ex., fentanyl)and non-diazepam benzodiazepines (ex., clon-azepam), which may confuse the clinical pic-ture and suggest diversion. These issues will bedetailed in sections below. Although EIAs arereproducible, inexpensive, and easy to perform,a disadvantage of EIA testing is that only theclass of drug is identified (ex., opiate or benzo-diazepine) and not the specific drug (ex., codeineor diazepam);2 further testing, explained in thenext section, is required to make a specific iden-tification.

Gas Chromatography and MassSpectroscopy Testing

To determine specific drugs and concentra-tions, gas chromatography followed by massspectroscopy is used. These tests are typicallyused in sequence. Simplistically, the urinet spec-imen is vaporized and injected into a port onthe gas chromatograph where the sample is dis-persed within a carrier gas that travels upward ona chemically treated column. Lighter moleculesin the specimen travel up faster and heavier onesmore slowly; hence, separation occurs. As themolecules reach top, an analyzer records con-centrations as separate peaks on a graph.2,9 Next,each peak is sent through the mass spectroscopy,which bombards the component with electrons,creating a predictable and reproducible microex-plosion resulting in an equally reproducible pat-tern of molecular strikes on a recording platecreating energy peaks viewed as a mass spec-trograph. These spectrograph patterns are com-pared by computer to a database of thousands ofmass spectrographs and the specific componentis identified (ex., morphine or diazepam).2,9

In short, gas chromatography separates andquantifies drug components and then mass

438 JOURNAL OF ADDICTIVE DISEASES

spectroscopy specifically identifies them. Gaschromatography followed by mass spectroscopyis considered the “gold standard” of urine tox-icology testing because it is 99% specific and99% sensitive.6 The use of EIA and gas chro-matography and mass spectroscopy urine testingto monitor various commonly prescribed opioidsand benzodiazepines is the subject of this articleand is presented below.10−12

Pain clinic chronic opioid patients have beenshown to submit significant numbers of abnor-mal urine toxicology tests, defined as the pres-ence of illicit substances, excess levels of theprescribed substance, or the absence of the pre-scribed substance.1 In one study of 470 paincenter patients, 44% abused substances, 20%used illicit non-opioid substances, 14% used ad-ditional opioids not prescribed, and 10% did notuse the opiate that was prescribed.13 In anotherpain center, testing of 196 patients found 32%to be mismanaging drugs; 60% of these wereusing non-prescribed opiates or diverting opi-ates and 40% of the 196 patients were primarilyabusing cocaine, with 11% of patients not takingthe prescribed opiate medication.14 In a reviewof several pain clinics, 25% to 44% of patientswere found to be abusing various substances ordiverting prescribed opioids, and this pattern ofdrug use was closely correlated with specific be-haviors, including repeated loss of prescriptions,excess pill consumption, visits without appoint-ments, frequent telephone calls to the clinic, andmultiple drug intolerances or “allergies,” behav-iors of which prescribing physicians should befully aware of and responsive to.15 In the primarycare setting, a study of 801 daily opioid patientsmanaged by family care physicians showed 24%to be using illicit substances.16

Accurate self-report of drug abuse and mis-use in these populations can be unreliable.12 In astudy of 110 patients in a methadone clinic, 21%reported illicit substance use in the month un-der study, yet toxicology demonstrated twice asmany (39%) to be using illicit drugs.17 A study ofmore than 800 chronic opiate patients found 24%to be using illicit substances, yet 46% of thesepatients adamantly denied substance abuse, evenwhen guaranteed anonymity.16 Therefore, urinedrug testing has become indispensable as an ob-jective, accurate, and reproducible aid in pa-

tient monitoring patients prescribed opioids orbenzodiazepines.3,13−18

Frequency of Urine Drug Testing

In pain management settings, it is recom-mended that urine drug screening be consideredat every clinic visit but actually collected ona random basis.12 Urine collection should berandom to eliminate patients’ feelings of beingsingled out or victimized and to assure collectionof a reasonably representative set of toxicologyspecimens over time, yielding a toxicologyprofile to assist in evaluating the individualpatient.19 Urine drug tests are not intended tobe the sole parameter by which patient man-agement decisions are made; rather, testing isonly a small part of the greater whole of patientmedical and psychosocial care and should beviewed in that context. For methadone treatmentprograms, federal government regulationsmandate weekly urine drug testing for the first90 days in treatment; after this period, healthcare providers may use clinical judgment to de-termine whether weekly testing should continueor if less frequent testing is warranted as longas 8 urine toxicology specimens are submittedannually; times of heightened patient stress ordrug relapse may call for increased frequency ofurine testing back to weekly.10 Ultimately, it isthe medical providers’ judgment in conjunctionwith the patients’ clinical status that shoulddetermine the urine testing schedule.10,12,19

Physician Awareness

To be useful, urine toxicology test results mustbe interpreted properly; however, studies showthat primary care physicians are not proficient atthis; none of 80 physicians in one study answeredall questions correctly on a brief yes-or-no rudi-mentary toxicology questionnaire, and only 20%answered half or more questions correctly.20 In asecond study, none of 114 physicians answeredall questions correctly and only 30% answeredhalf correctly. The 77 physicians who used urinedrug testing in their practices performed no bet-ter than the 37 physicians who did not, andthe authors called for increased physician ed-ucation regarding urine drug testing.21 The drug

Peter L. Tenore 439

summaries presented later in this article hope toaddress this deficit.

DRUGS OF INTEREST

Oxycodone and Opiate EIA Testing

In a study of 52 gas chromatography and massspectroscopy-confirmed oxycodone positiveurine specimens, only 30% were determinedto be positive by opiate EIA (i.e., the standardopiate EIA does not detect oxycodone in themajority of oxycodone specimens).22 In anreview of 8 commercially available opiate EIAs,the rates of detection of codeine, morphine,and semi-synthetic opiates were as follows:morphine (100%), codeine (100%), oxymor-phone (≤ 15%), meperidine (≤ 3%), hydro-morphone (≤ 60%), levorphanol (≤ 29%),and oxycodone (≤ 12%). This demonstratesthat the standard opiate EIA is not de-signed to and will not detect 100% of semi-synthetic opiates, including oxycodone.6

Thus, oxycodone produces mostly negativeopiate EIAs. In a survey of 359 primary carephysicians, only 12% knew that oxycodone isusually not detected by most opiate EIA screen-ing immunoassays.23 Oxycodone is a “semi-synthetic” opioid molecule, synthesized by thechemical addition of varying side-chains to amorphine molecule.24 The side-chains alter themorphine structure to the extent that the mor-phine antibody of the opiate EIA is unable toreliably bind to or “react” with oxycodone, re-sulting in frequent negative opiate EIAs.6,8,22,25

Patients taking oxycodone submitting the ex-pected negative opiate EIA urine in approxi-mately 90% of specimens may, because of physi-cian unawareness, stand accused of medicationdiversion and undergo sanctions, denial of med-ication, or clinic discharge. In one report, theauthors state:

We recently encountered a patient we sus-pected of abusing or misusing prescribedOxyContin©R (oxycodone). In order to de-termine whether the patient was taking theMEDICATION as prescribed, we ordereda urine-based immunoassay drug screen

(Opiate EIA). The results were negative;the patient appeared to not have oxycodonein his system. Based on these results, wedismissed the patient from our practice.26

If these providers were aware that oxycodoneand other semi-synthetics produced a significantamount of negative standard opiate EIAs, as seenin this case, and that an EIA specific for oxy-codone was available, the patient would not haveexperienced sanctioning.

The oxycodone EIA is an extremely reliabletest: in a study of 435 urine samples containingoxycontin, the oxycodone EIA demonstrated asensitivity of 99.1% and specificity of 99.8%.25

Medical providers can evaluate patients takingoxycodone who submit negative urine opiateEIAs with the specific oxycodone EIA; if oxy-codone is demonstrated, false accusations andunwarranted sanctions may be averted.26,27

However, if the oxycodone EIA does notfind oxycodone in an patient taking oxycodone,there are three major considerations. First, thereis the possibility that the patient is divertingor stockpiling medication, indicating a needfor further urine testing and clinical interven-tion. Second, some compliant patients havevery low urine oxycodone levels (under the300 ng/mL level of detection) and may inno-cently produce false-negative oxycodone EIAs.This can be seen in rapid metabolizers orin very low dose cases; in these instances,oxycodone can be detected by gas chromatog-raphy and mass spectroscopy.3,8,9,18 Third, oxy-codone patients submitting oxycodone negativespecimens may be substituting another individ-uals’ urine to avoid detection of drug abuse ordiversion. If urine substitution is suspected, asupervised specimen may be collected in a re-spectful manner or an oral fluid test that canbe administered by a staff member observingthe oral swab in the patients’ oral cavity can bedone, ensuring that the specimen belongs to thepatient.28

Semi-Synthetic Opiates

As in the case of oxycodone, other semi-synthetic opiates, including buprenorphine, oxy-morphone, oxycodone, hydromorphone, and


levorphanol, all produce a significant numberof negative standard urine opiate EIAs.3,6 Manyphysicians are unaware of this fact.17 Because, aswith oxycodone, the molecular shapes of semi-synthetic morphine-based opiates differ frommorphine, with side-chain substitutions they be-come poorly reactive with standard opiate EIAmorphine antibodies and frequently producenegative results.6,8,19 Therefore, negative opiateEIAs in patients taking levorphanol, hydromor-phone, buprenorphine, or other semi-syntheticsdo not necessarily indicate diversion. To pre-vent unfounded allegations, practitioners canmonitor semi-synthetic patients with the spe-cific EIAs available for oxycodone, buprenor-phine, or hydromorphone.18 These EIAs willverify semi-synthetic presence in those takingmedication properly and will reveal absence ofsemi-synthetics in those not taking medicationregularly or diverting it.27 If semi-synthetic spe-cific EIAs are unavailable, gas chromatogra-phy and mass spectroscopy testing may also beused to identify semi-synthetic opiates, includ-ing oxycodone.3,8,9 Providers should familiarizethemselves with which tests their toxicology lab-oratory uses.

Hydrocodone

Hydrocodone is a semi-synthetic and willusually not be detected by most standard opi-ate EIAs, as discussed in the previous section.18

However, there is a caveat to this statement; in2 of 8 commercially available opiate EIAs re-viewed, the EMIT II Plus Opiate Assay and theArchetict/Aeroset Opiate Assay-hydrocodonewas readily identified as an opiate, making it theexception to the rule that semi-synthetic opiatestypically present as opiate-negative with stan-dard opiate EIAs.6,18 Thus, it is critical that prac-titioners communicate with the laboratory andlearn which EIAs are in use. If the opiate EIAin use is one that readily identifies the semi-synthetic hydrocodone, expect positive opiateEIAs in hydrocodone patients; if the laboratorydoes not use one of the 2 hydrocodone-sensitiveEIAs, most opiate EIAs in patients taking hy-drocodone will be negative. Gas chromatogra-phy and mass spectroscopy may be used toidentify this substance.6,18 Given that diverted

hydrocodone has been implicated in more opi-oid analgesic overdose deaths than morphine,monitoring patients taking hydrocodone withongoing urine drug testing and the appropri-ate hydrocodone-sensitive EIA is an importantinitiative.4

Heroin

Approximately 30% of the weight of opiumpoppy fluid is comprised of opiate alkaloidsconsisting mostly of morphine with lesseramounts of codeine and other non-narcoticcompounds.24,29 By the chemical addition of 2acetyl groups to opium morphine, heroin (di-acetyl-morphine) is synthesized.30

Heroin is rapidly metabolized from di-acetyl-morphine to 6-mono-acetyl morphine (6-MAM), then to morphine, and then to morphine-6-glucuronide, all with short half-lives measuredin minutes such that that heroin becomes un-detectable in 40 minutes, 6-MAM in 4 to 12hours, morphine in 8 hours, and morphine-6-glucuronide in 48 hours. Because 70% to 80%of the heroin dose is recovered in the urine andall of these metabolites are readily detected bythe opiate EIA’s morphine antibody, heroin andits morphine-moiety metabolites are easily de-tected with standard opiate EIAs producing apositive opiate result at the 300 ng/mL level ofdetection for up to 2 days after a single intra-venous or inhaled heroin dose.31,32

6-MAM and Heroin Detection

Heroin (3,6-diacetyl-morphine) is rapidlymetabolized by liver cytochromes directly intothe molecule 6-MAM, making 6-MAM an idealcandidate for specific identification of heroinuse.5 In a landmark 1988 study of heroin metabo-lites, investigators measured morphine levelsand, for the first time, 6-MAM levels in 12 heroinusers to quantify urine morphine levels in thesecases, and to determine whether 6-MAM wasuseful to identify heroin use. Gas chromatog-raphy and mass spectroscopy detected 6-MAMlevels of 53 to 3,390 ng/mL (≥10 ng/mL = “pos-itive”) in 11 of 12 cases. Only 1 case with alow morphine level (1,414 ng/mL) was 6-MAMnegative.33 In another study of heroin users, 73%of 100 specimens were found to be positive for

Peter L. Tenore 441

6-MAM.34 Because 6-MAM is the first productof heroin metabolism and no other compoundwith the exception of heroin yields 6-MAM, thepresence of 6-MAM in the urine is unequiv-ocal evidence of heroin use and, thus, an ex-ceedingly important forensic urine monitoringtool.33,34

Although evidence of 6-MAM proves heroinuse, a limitation of 6-MAM testing is its shorthalf-life, rendering it detectable for only up to12 hours after heroin use and it can be missedif heroin use occurred prior to that.32 Thus, re-peated testing for 6-MAM may be necessary toultimately identify heroin use in patients withpositive opiate EIAs who are suspected of butdeny heroin use.34,35

Several commercial 6-MAM EIA tests areavailable and, in a study of 525 6-MAM pos-itive specimens, these immunoassays proved tobe 98% sensitive and 98% specific, making the6-MAM EIA an important tool to assist patientmanagement.5,36

Morphine Levels in Heroin Use

After 6-MAM, heroin rapidly metabolizes tomorphine and, depending when samples are col-lected in relation to heroin use, morphine lev-els vary. In one study of 12 heroin users, ran-domly collected urine morphine levels rangedfrom 1,400 to 87,350 ng/mL, with half of thecases having morphine levels of 8,000 ng/mL orhigher.33 In a larger study of 63 heroin users, themean urine morphine level was 62,370 ng/mL(range: 7,100 to 476,000 ng/mL) and 80% ofparticipants demonstrated morphine levels >

15,000 ng/mL. Thus, a morphine level greaterthan 15,000 ng/mL is highly suggestive of heroinuse but is certainly not absolute proof becausemorphine use or abuse and codeine use or abusemay also produce morphine at these levels.33,34

Because the presence of morphine in the urinespecimen can indicate heroin use but can alsoindicate the use of morphine, codeine, or poppyseeds, to better identify heroin use, two othermodalities independent of the absolute morphinelevel can link morphine positivity to heroin use.The first is the 6-MAM EIA test, which whenpresent proves heroin use, but if absent doesnot exclude heroin use and repeat testing may

be needed.36 The second modality is the mor-phine:codeine ratio, which can be helpful in thesetting of a negative 6-MAM in a heroin user(discussed in the next section).34

The Morphine/Codeine Ratio

Urine samples from heroin users typicallycontain substantial amounts of morphine withlesser amounts of codeine (reflecting poppyfluid contents) and dividing the morphine levelby the codeine level yields the valuable mor-phine:codeine ratio. A morphine:codeine ratiogreater than 2:1 as determined by gas chro-matography and mass spectroscopy has beenshown to be a reliable indicator of heroin use. In astudy of 100 heroin users, morphine:codeine ra-tios were greater than 20:1 in the majority (84%)of cases, greater than 10:1 in 90% of cases, and2:1 or greater in 94% of cases, demonstratingthat a morphine:codeine ratio greater than 2:1is corroborative evidence of heroin use.34 Theonly non-heroin drug combination that couldproduce a morphine:codeine ratio greater than2:1 would be a patient using or abusing mor-phine in larger amounts and using or abusingcodeine in smaller amounts simultaneously. Thiscombination would conceivable produce a mor-phine:codeine ratio mimicking that of heroin(i.e., greater than 2:1) and a careful drug his-tory becomes critical in this case.

Codeine

Codeine is nearly identical to morphine instructure24 so that standard urine opiate EIAswill easily detect codeine at the 300 ng/mL levelof detection.6,8 Maximum therapeutic codeinelevel by urine gas chromatography and massspectroscopy should not exceed 15,000 ng/mL;levels higher than 15,000 ng/mL are indicativeof codeine abuse.37,38

Codeine is metabolized by cytochrome 2D6 tomorphine;39 thus, codeine patients will have bothcodeine and morphine detectable in gas chro-matography and mass spectroscopy urine sam-ples for up to 48 hours after a single dose.24,37

Although both codeine and morphine are eas-ily identified by opiate EIAs and this informa-tion is readily available, only 29% of physicianswho used urine drug testing in their practices


were aware that codeine metabolizes to mor-phine, placing legitimate patients taking codeineat risk for accusations of morphine abuse.21

Because codeine metabolizes to morphine, amorphine:codeine ratio can also be determinedin codeine users; although heroin produces amorphine:codeine ratio of 2:1 or greater and isoften much greater (ex., > 10:1), codeine pro-duces a morphine:codeine ratios of less than2:1. If a patient taking codeine demonstrates amorphine:codeine ratio of 2:1 or greater, this istoo much morphine to be explained by codeineand other morphine sources, including heroin,poppy seeds, and morphine itself, should beconsidered.34,37,38

Codeine without Morphine

Rare patients lack the liver cytochrome 2D6enzyme needed to convert codeine to morphine,meaning that they cannot metabolize codeine tomorphine. These urine specimens will showncodeine only and no morphine, rendering themorphine:codeine ratio ineffective in differen-tiating drug use; supervised urine specimensor oral fluid specimens (administered directlyobserved by staff members) will show onlycodeine.40

Another source of codeine-only specimenscould be patients who are not taking their pre-scribed codeine (stockpiling or diverting) andwho may spike drug-free urine samples withcrushed codeine tablets to maintain the appear-ance of a positive opiate EIA. These urine sam-ples will have codeine only without morphinebut examination of urine specimens will reveal acharacteristic white precipitate along the bottomof the urine container.28

Codeine normally produces positive opiateEIAs. If confirmation is desired in adherentcases, gas chromatography and mass spec-troscopy testing will reveal codeine or mor-phine levels of < 15,000 ng/mL and a mor-phine/codeine ratio of less than 2:1. The heroinmetabolite 6-MAM EIA will be negative. In pa-tients taking codeine, codeine or morphine levelsof > 15,000 ng/mL indicate codeine abuse37,38

and a morphine:codeine ratio greater than 2:1indicate heroin use.34,41

Poppy Seed

As a product of the opium poppy, poppyseeds contain small amounts of morphine andcodeine and, under proper conditions (ex., con-sumption of 1 poppy Danish streusel pastry), canreadily produce positive opiate EIAs.42 Manyphysicians are not aware of this poppy seed ef-fect. In a recent survey of 359 emergency roomphysicians, the majority (60%) were unawarethat poppy seeds could produce a positive opiateEIA.23

Goods baked with poppy seeds are widelyavailable. Typically, poppy seed bagels, muffins,Danish, and Streusel contain morphine inamounts of 1, 2, 6, and 6 mg per piece, respec-tively, so that consumption of a single muffin,Danish, Streusel, or 2 bagels can produce a pos-itive opiate EIA at the 300 ng/mL morphine levelof detection and the test can remain positive for24 hours after ingestion.42

In a classic 1987 study, consumption of 3poppy seed bagels produced positive opiate EIAswith gas chromatography and mass spectroscopymorphine levels of 2,797 ng/mL at 3 hours, and676 ng/mL at 22 hours (codeine levels were 214and 16 ng/mL, respectively).43 In another inves-tigation of 10 participants who consumed mea-sured amounts of whole poppy seeds reflectingamounts in baked goods, and who underwentmultiple urine sampling over 24 hours, morphinewas found in all cases at 24 hours. Two morphinelevels were more than 2,000 ng/mL (2,635 and2,199 ng/mL), but all other samples were lessthan 1,700 ng/mL, with most poppy seed mor-phine concentrations less than 1,000 ng/mL. Theauthors concluded that a morphine level of 3,000ng/mL or less can be explained by poppy seedingestion (but this can also be due to heroin ormorphine use, see discussion below) and thatmost cases of poppy seed ingestion will havemorphine levels less than 1,000 ng/mL.44

Poppy Seed Morphine:Codeine Ratio

The morphine:codeine ratio in poppy seedingestion, like heroin ingestion, is also 2:1 orgreater (ex., 13:1, 42:1), consistent with opiumpoppy fluid as the opiate source for both heroinand poppy seeds. In one study, the average

Peter L. Tenore 443

morphine:codeine ratio at 22 hours post-poppyseed ingestion was 45:1.43 Other poppy seedstudies also show morphine:codeine ratios ofmore than 2:1 (i.e., 19:1 to 295:1); thus, highmorphine:codeine ratios with low morphine lev-els (< 3,000 ng/mL, usually < 2,000 ng/mL) areconsistent with poppy seed consumption and donot automatically indicate heroin abuse.45

Poppy Seed Ingestion versus Heroin Use

It can be difficult to determine whether pos-itive opiate EIAs are the result of poppy seedingestion or heroin use,38 both being derivedfrom the same source (opium poppy). Gas chro-matography and mass spectroscopy will showthat poppy seeds contain morphine and codeineindistinguishable from that of heroin and in thesame ratio found in heroin (2:1 or greater), butabsolute levels of morphine and codeine are typ-ically lower with poppy seeds, with morphine <

3,000 ng/mL and codeine < 300 ng/mL; mostpoppy seed cases produce urinary morphine lev-els less than 1,000 ng/mL.44

High morphine levels (> 3,000 ng/mL witha morphine:codeine ratio of 2:1 or greater) aremost likely due to heroin use but any morphinelevel, even ones as low as 1,000 ng/mL with amorphine:codeine ratio of 2:1 or greater, can becaused by heroin use.33 Because poppy seed in-gestion and heroin use can both produce lowermorphine levels,38 further testing for 6-MAMmay be needed to identify heroin use with cer-tainty in these low level morphine cases.33−35,46

In some cases, the only way to prove thatmorphine is due to poppy seed ingestion is tohave patients discontinue ingesting poppy seedproducts and observe opiate EIAs reverting tonegative levels in 48 hours. All patients are ad-vised to avoid poppy seed products to avoid un-necessary positive opiate EIAs and possible un-founded sanctions from providers.

If 6-MAM is repeatedly negative and mor-phine is less than 3000 ng/mL with a mor-phine:codeine ratio of 2:1 or greater, it is impos-sible to differentiate poppy seeds from heroin.The clinical impression of the medical providerand patient history of poppy seed ingestion inconjunction with repeated gas chromatographyand mass spectroscopy and 6-MAM testing is

needed to finally identify the true source of opi-ate. Nonetheless, morphine levels greater than3,000 ng/mL, with a morphine:codeine ratio of2:1 or greater, usually indicate heroin use andthe 6-MAM EIA proves it if positive.34,38

Fluoroquinolones

The only substances that normally produce100% positive opiate EIAs are the morphine-based opiates such as morphine, heroin, codeine,and poppy seeds and the semi-synthetic hy-drocodone (if a hydrocodone-sensitive opiateEIA is in use).8,19

Fluoroquinolone antibiotics, such asofloxacin or ciprofloxacin, can also producepositive opiate EIAs, potentially leading to un-founded accusations of drug abuse and dismissalor other disciplinary action for patients enrolledin pain clinics or drug treatment programs.47,48

Fluoroquinolone opiate EIA positivity isclosely correlated to peak quinolone urine levels.In one investigation, urine collected 6 to 8 hours(peak levels) after ofloxacin or levofloxacin in-gestion produced 100% positive (false-positive)opiate EIAs in all 6 cases, with morphine lev-els registering just above the 300 ng/mL cut-off, even though there was no morphine presentin the specimens.49 Why opiate EIAs identifyfluoroquinolones as morphine itself is unknownsince chemical structures are completely dis-similar.24 Individuals with positive opiate EIAsshould be questioned regarding fluoroquinoloneuse and can be evaluated with gas chromatogra-phy and mass spectroscopy testing, which willdemonstrate no opiates present in these speci-mens in the absence of opiate use or abuse.50

Buprenorphine

Buprenorphine is a morphine-based, semi-synthetic molecule, which is a partial agonist atbrain opiate mu-receptors.24 Due to the additionof extensive side chains to the base morphinemolecule to create buprenorphine, altering theappearance extremely from that of morphine;the morphine core is nearly unrecognizable in2-dimensional depictions of buprenorphine.24

Due to this configurational alteration, the mor-phine antibody in standard opiate EIAs will not


react with buprenorphine, yielding negative opi-ate EIAs in these individuals.8,51

However, fortunately highly sensitive andhighly specific buprenorphine EIA tests areavailable and should be used to monitor patientstaking buprenorphine. One buprenorphine EIAshowed a specificity of 97% and a sensitivity of99.5%52 and another “demonstrated a sensitivityand specificity of 100%,”54 making these testsessential to the management of the buprenor-phine patient.53,55

However, conversely if testing in patientstaking buprenorphine reveals the absence ofbuprenorphine, then diversion, stockpiling, orselling of medication becomes a concern. In arecent study of widespread buprenorphine di-version, medical personnel were alerted by theabsence of buprenorphine in monitoring urinespecimens with the buprenorphine EIA.54 Onquestioning, only 43% of 71 diversion cases ad-mitted to diversion, reinforcing the importanceof ongoing urine drug monitoring as a necessaryobjective tool to improve patient monitoring andenhance patient management.1,3,53

Fentanyl

Fentanyl is a wholly synthetic (as opposed tosemi-synthetic) opiate and, not being morphine-based, produces negative opiate EIAs.55 Othercommon synthetic opiates include methadone,propoxyphene, meperedine, tramadol, and pen-tazocine. These synthetic opioids do not re-act with the opiate EIA morphine antibodyand will produce negative opiate EIA results.Gas chromatography and mass spectroscopy andmore specific EIA testing (discussed below)can be used to confirm the presence of thesesynthetics.19,25

Because fentanyl diversion is a growing prob-lem in the United States,56 prescribers need tobe aware of fentanyl urine testing characteris-tics; fentanyl does not produce positive standardopiate EIAs.25 The absence of positive opiateEIAs in patients taking fentanyl, although a nor-mal occurrence that is consistent with fentanyl,should not obviate the need for further con-firmatory testing to explicitly demonstrate thepresence of fentanyl. A study of fentanyl patchpatients showed a sensitivity and specificity

of 98% for the fentanyl urine EIA.57 Severalfentanyl-specific EIA tests available are capableof detecting minute concentrations of fentanylin urine specimens and can be used to moni-tor patients taking fentanyl to assure this com-pound is present in patient urine specimens.57,58

Providers should communicate with their tox-icology laboratories to determine whether afentanyl EIA is available and apply it to pa-tients taking fentanyl in accordance with clinicalneeds.

If patients taking fentanyl are submitting pos-itive standard opiate EIAs and these positiveswere attributed to fentanyl (which is not possi-ble), some morphine-based drug is being used orabused in addition to or in lieu of fentanyl, andgas chromatography and mass spectroscopy canbe used for identification.6

Methadone

Methadone is a wholly synthetic opioidmolecule, which is not structurally related tomorphine; therefore, methadone does not reactwith the standard opiate EIA morphine antibodyand will yield negative opiate results in screeningtoxicology tests.8 Providers who wish to mon-itor patients taking methadone can use one ofthe commercially available methadone EIAs thathave been shown to be 98% sensitive and 98%specific.59

Sertraline

Patients taking the anti-depressant sertralinecan produce sporadic false-positive benzodi-azepine EIA urine toxicology specimens.60 Un-founded accusations of benzodiazepine abuse inthese patients may arise. In one study, 16 of 50POSITIVE Benzodiazepine EIAs were submit-ted by patients taking sertraline who were not in-gesting benzodiazepines. In a review phase of thesame study, false-positive benzodiazepine EIAscaused by sertraline were found in 26% of 2,447patients taking sertraline urine specimens.61 Re-cently, the benzodiazepine EIA test manufac-turer released the following statement:

patients taking therapeutic doses of Ser-traline (Zoloft©R ) of 100–200 mg per daycan test positive for benzodiazepines.

Peter L. Tenore 445

An unidentified metabolite of Sertraline inurine is responsible for the cross-reactivityas unmetabolized Sertraline is not presentin sufficient quantities to cause a positivetest.62

The chemical structures of sertraline and itsurinary metabolite, des-methyl-sertraline, bear astriking similarity to diazepam,24 which likelyenables the benzodiazepine EIA to react causinga false-positive benzodiazepine result.62 Sertra-line is now listed as one of the compounds, alongwith diazepam and alprazolam, which can causea positive benzodiazepine EIA result in the 2008EIA cross-reactivity list.8

Patients taking Sertraline who submit pos-itive benzodiazepine EIAs and deny benzodi-azepine use should not automatically be accusedof benzodiazepine abuse; they may undergo gaschromatography and mass spectroscopy test-ing, which can confirm the absence of benzo-diazepines, indicating a false-positive EIA dueto sertraline. In cases of patients taking sertralinewho are using or abusing benzodiazepines, gaschromatography and mass spectroscopy can beused to demonstrate the presence and concentra-tion of the specific benzodiazepine.61

Clonazepam and Lorezepam

Patients taking clonazepam have been shownto produce a significant number of negative ben-zodiazepine EIAs due to lower reactivity of clon-azepam with the EIA’s diazepam antibody.63

Similarly, lorazepam has also been show toproduce mostly or all negative benzodiazepineEIAs for the same reason. In a study of 4 dif-ferent manufacturers’ benzodiazepine EIAs, 38different benzodiazepines and their metaboliteswere evaluated to determine the rate of ben-zodiazepine detection for each benzodiasepineEIA. Results showed that all immuno-assaystested detected diazepam and alprazolam; how-ever, none detected clonazepam or lorazepam.63

In an analysis of urine levels in 53 patients tak-ing benzodiazepine, 10% of whom were takinglorazepam, none of three commercially avail-able standard benzodiazepine EIAs were able toidentify any lorazepam in any patient.64 Finally,a study of one popular commercially available

benzodiazepine EIA’s ability to react with 15different benzodiazepines demonstrated “good”reactivity (i.e., antibody binding) to diazepam,only “moderate” reactivity to clonazepam, and“low” reactivity to lorazepam, indicating thatnegative benzodiazepine EIAs with clonazepamand lorazepam are expected, normal results.65

Because these negative benzodiazepine EIAsmay lead to accusations of benzodiazepine diver-sion, providers should consider gas chromatog-raphy and mass spectroscopy when needed todemonstrate clonazepam or lorazepam in thesespecimens.9 However, if gas chromatographyand mass spectroscopy fail to demonstrate clon-azepam or lorazepam in patients who say theyare taking these medications, then diversion ormissed doses should be considered.

Conversely, if patients taking clonazapam orlorazepam are submitting mostly or all posi-tive benzodiazepine EIAs (not a clonazepamor lorazepam pattern) the use of other non-clonazapam or non-lorazepam benzodiazepines,such as diazepam and alprazolam, is sug-gested and gas chromatography and mass spec-troscopy can reliably determine their types andconcentrations.9

CONCLUSION

We have reviewed the use of screening urineEIAs and gas chromatography and mass spec-troscopy to verify legitimate prescriptions ofspecific drugs and to identify abused substancesin the urine in those claiming legitimate pre-scriptions. Standard opiate EIAs identify onlymorphine, heroin, hydrocodone, and codeine as“positive” opiates; if the exact drug (i.e., mor-phine) and the concentration is desired, then gaschromatography and mass spectroscopy must beused to supply this information.

Heroin use typically yields morphine lev-els greater than 3,000 ng/mL and poppy seedingestion yields less than 3,000 ng/mL. Mostheroin samples yield morphine levels in excessof 15,000 ng/mL, with morphine:codeine ra-tios greater than 2:1, usually 10:1 and greater.6-MAM, a heroin metabolite, is definitive evi-dence of heroin use, although short lived under12 hours. A morphine:codeine ratio greater than


2:1 indicates heroin or poppy seed use; a ratio ofless than 2:1 is consistent with codeine use.

Synthetic opiates (non-morphine based), suchas fentanyl, methadone, and meperidine, willbe opiate EIA negative. Semi-synthetic opiates,such as oxycodone and hydromorphone, usu-ally yield negative opiate EIAs but, being distantmorphine congeners, will also produce sporadicpositive opiate EIAs (i.e., mixed positive andnegative results). Specific EIAs and gas chro-matography and mass spectroscopy can identifysynthetic and semi-synthetic opioids. Providersshould consult with the toxicology laboratory todetermine which tests are available.

Fluoroquinolones such as ciprofloxacin canproduce false-positive opiate EIAs. Gas chro-matography and mass spectroscopy can be usedfor clarification in all of these instances. Ser-traline can cause sporadic false-positive benzo-diazepine EIAs via sertraline metabolites’ re-sembling diazepam. Clonazepam and lorazepamwith structures dissimilar to diazepam will fre-quently produce false-negative benzodiazepineEIAs and gas chromatography and mass spec-troscopy may be used to confirm their presence.Urine toxicology testing is an important partof comprehensive care for individuals attendingdrug treatment programs or receiving chronicopioid or benzodiazepine therapy and should beconsidered as an objective test within a greaterintegrated psychosocial and medical format andtoxicology results should never be interpreted ina vacuum, but rather always within the broaderclinical patient context.

REFERENCES

1. Hamett-Stabler C, Webster L. Clinical guide tourine drug testing monograph. Newark, NJ: University ofMedicine and Dentistry of New Jersey, Center for Contin-uing and Outreach Education, 2008.

2. Webster LR, Dove B. Avoiding opioid abuse whilemanaging pain: a guide for practitioners. North Branch,MN: Sunrise Press, 2007.

3. Gourlay DL, Heit HA, Caplan YH. Urine toxicol-ogy testing in clinical practice: dispelling the myths anddesigning strategies. J Calif Acad Fam Pract 2006; 1:3–22.

4. Paulozzi L, Budnitz D, Yongli X. Increasing deathsfrom opioid analgesics in the United States. Pharmacoepi-demiol Drug Saf 2006; 15:618–27.

5. Holler JM, Bosy TZ, Klette KL, Wiegand R,Jemionek J, Jacobs A. Comparison of the Microgenics CE-DIA heroin metabolite (6-AM) and the Roche AbuscreenONLINE opiate immunoassays for the detection of heroinuse in forensic urine samples. J Anal Toxicol 2004; 28:489–93.

6. Reisfield GM, Salazar E, Bertholf RL. Rational useand interpretation of urine drug testing in chronic opioidtherapy. Ann Clin Lab Sci 2007; 37:301–14.

7. Schneider RS, Lindquist P, Tong-in Wong E, Ruben-stein E, Ullman EF. Homogeneous enzyme immunoassayfor opiates in urine. Clin Chem 1973; 19:821–5.

8. Siemens Healthcare Diagnostics, Inc. EMIT II Plus©R

Immunoassay Analyzer for detection of drugs of abuse(DAUs), package insert and Cross-Reactivity List data.Deerfield, IL: Siemens Healthcare Diagnostics, Inc., 2008.

9. Hewlett-Packard HP Gas Chromatograph Model5890-Mass Spectrometer Model 5970 instruction manualand package insert data. Foster City, CA: Agilent Tech-nologies, Quantum Analytics, Inc., 2005.

10. NYS Mental Hygiene Law: Sections 19.05(f),19.07(b), 23.01. Requirements for the operation ofchemotherapy substance abuse programs. Title 14 of theofficial compilation of codes, rules and regulations of theState of New York. Part 828, Section 828.12. 2000.

11. Bush DM. The U.S. mandatory guidelines for federalworkplace drug testing programs: current status and futureconsiderations. Forensic Sci Int 2008; 174:111–19.

12. Katz N, Fanciiuollo G. Role of urine toxicology test-ing in the management of chronic opioid therapy. Clin JPain 2008; 18:S76–82.

13. Michna E, Jamison RN, Pham LD, Ross EL, JanfazaD, Nedeljkovic SS, Narang S, Palombi D, Wasan AD. Urinetoxicology screening among chronic pain patients on opioidtherapy: frequency and predictability of abnormal findings.Clin J Pain 2007; 23: 173–9.

14. Ives TJ, Chelminski PR, Hammett-Stabler CA, Mal-one RM, Perhac JS, Potisek NM, Shilliday BB, DeWaltDA, Pignone MP. Predictors of opioid misuse in patientswith chronic pain: a prospective cohort study. BMC HealthServ Res 2006; 6:46.

15. Katz N, Sherburne S, Beach, M. Behavioral mon-itoring and urine toxicology testing in patients receivinglong-term opioid therapy. Anesth Analg 2003; 97:1097–102.

16. Fleming MF, Balousek ST, Kessig CI, Mundt M,Brown DD. Substance use disorders in a primary care sam-ple receiving daily opioiod therapy. J Pain 2007; 8:573–82.

17. Chermack ST, Roll J, Reilly M, Davis L, Kilaru U,Grabowski J. Comparison of patient self-reports and uri-nalysis results obtained under naturalistic methadone treat-ment conditions. Drug Alcohol Depend 2000; 59:43–9.

18. Smith ML, Hughes RO, Levine B, Dickerson S,Darwin WD, Cone EJ. Forensic drug testing for opi-ates. VI. Urine testing for hydromorphone, hydrocodone,oxymorphone, and oxycodone with commercial opiate

Peter L. Tenore 447

immunoassays and gas chromatography-mass spectrome-try. J Anal Toxicol 1995; 19:18–26.

19. Compton P. The role of urine toxicology inchronic opioid analgesic therapy. J Pain Manag 2007; 8:166–72.

20. Reisfield GM, Webb FJ, Bertholf RL, Sloan PA, Wil-son GR. Family physicians’ proficiency in urine drug testinterpretation. J Opioid Manag 2007; 3:333–37.

21. Reisfield GM, Bertholf R, Barkin RL, Webb F, Wil-son G. Urine drug test interpretation: what do physiciansknow. Clin J Pain 2007; 3:80–6.

22. Dunn KE, Sigmon SC, McGee MR, Heil SH, Hig-gins ST. Evaluation of ongoing oxycodone abuse amongmethadone-maintained patients. JSAT 2008; 35:451–56.

23. Levy S, Harris SK, Sherritt L, Angulo M, KnightJR. Drug testing of adolescents in ambulatory medicine:physician practices and knowledge. Arch Pediatr AdolescMed 2006; 160:146–50.

24. Brunton L, Lazo J, Parker K. Goodman and Gilman’sthe pharmacological basis of therapeutics. 11th ed. NewYork, NY: McGraw-Hill, 2005.

25. Reisfield GM, Bertholf RL. “Practical guide” tourine drug screening clarified. Mayo Clin Proc 2008;83:848–9.

26. Von Seggern R, Fitzgerald CP, Adelman LC, Adel-man U. Laboratory monitoring of OxyContin (Oxycodone):clinical pitfalls. Headache: JHAFP 2004; 44:44–7.

27. Backer RC, Monforte JR, Poklis A. Evaluation ofthe DRI oxycodone immunoassay for the detection of oxy-codone in urine. J Anal Toxicol 2005; 29:675–77.

28. CSAT: the Center for Substance Abuse Treatment.Medication-assisted treatment for opioid addiction in opi-oid treatment programs. Treatment Improvement Protocol(TIP) Series, No. 43. DHHS Publication No. (SMA) 05–4048. Rockville, MD: Substance Abuse and Mental HealthServices Administration, 2005

29. Narayanaswami K, Golani HCC, Dua RD. Assay ofmajor and minor constituents of opium samples and studiesof their origin. Forensic Sci Int 1979; 14:181–90.

30. Francis PS, Adcock JL, Costin JW, Purcell SD, Pf-effer FM, Barnett NW. Chemiluminescene detection ofopium poppy alkaloids. J Pharmacol and Biochem Anal2008; 4:508–18.

31. Rook EJ, van Ree JM, van den Brink W, HillebrandMJ, Huitema AD, Hendriks VM, Beijnen JH. Pharmacoki-netics and pharmacodynamics of high doses of pharma-ceutically prepared heroin, by intravenous or by inhalationroute in opioid-dependent patients. Basic Clin PharmacolToxicol 2006; 98:86–96.

32. Smith ML, Shimomura ET, Summers J, PaulBD, Jenkins AJ, Darwin WD, Cone EJ. Urinary excre-tion profiles for total morphine, free morphine, and 6-acetylmorphine following smoked and intravenous heroin.J Anal Toxicol 2001; 25:504–14.

33. Mule SJ, Casell GA. Rendering “the poppy seed de-fense” defenseless: identifying 6-monoacetylmorphine in

the urine by gas chromatography/mass spectroscopy. ClinChem 1988; 34:1427–30.

34. O’Neal CL, Poklis A. Detection of acetylcodieineand 6-monoacetyl morphine in opiate positive urines.Forensic Sci Int 1998; 95:1–14.

35. Rook EJ, Huitema AD, van den Brink W, vanRee JM, Beijnen JH. Pharmacokinetics and pharma-cokinetic variability of heroin and its metabolites: re-view of the literature. Curr Clin Pharmacolog 2006; 1:109–18.

36. Jenkins AJ, Lavins ES, Snyder A. Evaluation of thecedia heroin metabolite 6-MAM immunoassay with urinespecimens from a criminal justice drug-testing program. JAnal Toxicol 2005; 29:201–4.

37. Posey BL, Kimble SN. High-performance liquidchromatographic study of codeine, norcodeine, and mor-phine as indicators of codeine ingestion. J Anal Toxicol1984; 8:68–74.

38. MacDonald D, Ferguson J. Chapter 3: Drug UrineToxicology Testing. In The Medical Review Officer. 127–243. 2002. American Society of Addiction Medicine Pub-lications. Chevy Chase, MD.

39. Kircheimer J, Schmidt H, Tzvetkov M, Keulen JT,Lotsch J, Roots I, Brockmoller J. Pharmacokinetics ofcodeine and its metabolite morphine in ultra-rapid metab-olizers due to CYP2D6 duplication. PharmacogenomicsJournal 2007; 7:257–65.

40. Susce MT, Murray-Carmichael E, de Leon J. Re-sponse to hydrocodone, codeine and oxycodone in aCYP2D6 poor metabolizer. Prog NeuropsychopharmacolBiol Psychiatry 2006; 30: 1356–8.

41. Brockmoller J, Schmidt H, Roots I, Kircheiner J.CYP2D6 ultrarapid metabolism and morphine/codeine ra-tios: was it codeine or heroin? J Anal Toxicol 2008; 32:178–82.

42. Selavka CM. Poppy seed ingestion as a contribut-ing factor to opiate-positive urinalysis results: the Pacificperspective. J Forensic Sci 1991; 36:685–96.

43. Struempler RE. Excretion of codeine and morphinefollowing ingestion of popoy seeds. J Anal Toxicol 1987;11:97–9.

44. Hayes LW, Krasselt WG, Mueggler PA. Concen-trations of morphine and codeine in serum and urineafter ingestion of poppy seeds. Clin Chem 1987; 33:806.

45. Meadway C, George S, Braithwaite R. Opiate con-centrations following the ingestion of poppy seed products-evidence for “the poppy seed defense.” Forensic Sci Int1998; 96:29–38.

46. Rook EJ, Huitema AD, van den Brink W, van ReeJM, Beijnen JH. Population pharmacokinetics of heroinand its major metabolites. Clinical Pharmacokinet 2004;45:401–17.

47. Straley CM, Cecil EJ, Herriman MP. Gatifloxacin in-terference with opiate urine drug screen. Pharmacotherapy2006; 26:435–9.


48. Meatherall R, Dai J. False-positive EMIT IIopiates from ofloxacin. Ther Drug Monit 1997; 19:98–9.

49. Baden L, Horowitz G, Eliopoulos G. Quinolones andfalse-positive urine screening for opiates by immunoassaytechnology. JAMA 2001; 286:3115–9.

50. Zacher JL, Givone DM. False-positive urine opiatescreening associated with fluoroquinolone use. Ann Phar-macother 2004; 38:1525–8.

51. Hull MJ, Bierer MF, Griggs DA, Long WH, NixonAL, Flood JG. Urinary buprenorphine concentrations inpatients treated with suboxone as determined by liq-uid chromatography-mass spectrometry and CEDIA im-munoassay. J Anal Toxocol 2008; 32:516–21.

52. Bottcher M, Beck O. Evaluation of buprenorphineCEDIA assay versus GC-MS and ELISA using urine sam-ples from patients in substitution treatment. J Anal Toxicol2005; 29:769–76.

53. Winstock AR, Lea T, Jackson AP. Methods and mo-tivations for buprenorphine diversion from public opioidsubstitution treatment clinics. J Addict Dis 2009; 28:57–63.

54. Kosten TR, Fiellin DA. U.S. National Buprenor-phine Implementation Program. Buprenorphine for office-based practice: consensus conference overview. Am J Ad-dict 2004; 13:S1–7.

55. Kaferstein H, Sticht G. Comparison of nonradioac-tive microtiter plate enzyme immunoassays for the sen-sitive detection of fentanyl. Forensic Sci Int 2000; 11:353–7.

56. Poklis A. Fentanyl: a review for clinical and analyt-ical toxicoligists. J Toxicol 1995; 33:439–44.

57. Poklis A, Backer R. Urine concentrations of fentanyland norfentanyl during application of Duragesic transder-mal patches. Anal Toxicol 2004; 28:422–5.

58. Mao CL, Zientek KD, Colahan PT, Kuo MY, LiuCH, Lee KM, Chou CC. Development of an enzyme-linkedimmunosorbent assay for fentanyl and applications of fen-tanyl antibody-coated nanoparticles for sample preparationJ Pharm Biomed Anal 2006; 41:1332–41.

59. Cheever ML, Armendariz GA, Moody DE. De-tection of methadone, LAAM, and their metabolites bymethadone immunoassays. J Anal Toxicol 1999; 23:500–5.

60. Fitzgerald RL, Herold DA. Improved CEDIA benzo-diazepine assay eliminates sertraline crossreactivity. J AnalToxicol 1997; 21:32–5.

61. Lum G, Mushlin B, Farney L. False-positive ratesfor the qualitative analysis of urine benzodiazepinesand metabolites with the reformulated Abbott Multigentreagents. Clin Chem 2008; 54:220–1.

62. Dade-Behring Corporation. Integrated services divi-sion. Newark, DE: Personal Communication, 2008.

63. Manchon M, Verdier MF, Pallud P, Vialle A, BesemeF, Bienvenu J. Evaluation of EMIT-TOX Enzyme Im-munoassay for the analysis of benzodiazepines in serum:usefulness and limitations in an emergency laboratory. JAnal Toxicol 1985; 9:209–12.

64. Augsburger M, Rivier L, Mangin P. Comparison ofdifferent immunoassays and GC-MS screening of benzodi-azepines in urine. J Pharm Biomed Anal 1998; 18:681–7.

65. Huang W, Moody DE. Immunoassay detection ofbenzodiazepines and benzodiazepine metabolites in blood.J Anal Toxicol 1995; 19:333–42.

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Advance Urine Toxicology Testing Article