Oral Fluid Drug Testing of Chronic Pain Patients. II. Comparison of Paired Oral Fluid and Urine Specimens

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1 Journal of Analytical Toxicology 2012;36:75 80 doi: /jat/bkr019 Article Oral Fluid Drug Testing of Chronic Pain Patients. II. Comparison of Paired Oral Fluid and Urine Specimens Rebecca Heltsley 1, Anne DePriest 1, David L. Black 1,2, Dennis J. Crouch 1, Tim Robert 1, Lucas Marshall 1, Viola M. Meadors 1, Yale H. Caplan 3,4 and Edward J. Cone 5,6 * 1 Aegis Sciences Corporation, 515 Great Circle Road, Nashville, Tennessee, 2 Vanderbilt University, Department of Pathology, Nashville, Tennessee, 3 University of Maryland, School of Pharmacy, Baltimore, Maryland, 4 National Scientific Services, 3411 Phillips Drive, Baltimore, Maryland, 5 Johns Hopkins School of Medicine, Baltimore, Maryland, and 6 ConeChem Research, Severna Park, Maryland * Author to whom correspondence should be addressed. Edwardcone@verizon.net. A clinical study was conducted to compare the use of oral fluid to urine for compliance monitoring of pain patients. Patients (n 5 133) undergoing treatment for chronic pain at four clinics participated in the study and provided paired oral fluid and urine specimens. Oral fluid specimens were collected with Quantisal TM saliva collection devices immediately following urine collection. Oral fluid specimens were analyzed for 42 drugs and/or metabolites by validated liquid chromatography tandem mass spectrometry procedures. Accompanying urine specimens were initially screened by immunoassay and non-negative results were confirmed. Of the 1544 paired tests, 329 (21.3%) drug analytes were positive, and 984 (63.7%) were negative for both specimens resulting in an overall agreement of 85%. There were 83 (5.4%) analyte results that were positive in oral fluid and negative in urine, and 148 (9.6%) were negative in oral fluid and positive in urine for an overall disagreement of 15%. Cohen s Kappa value was 0.64, indicating substantial agreement. The primary exceptions to agreement were the lower detection rates for hydromorphone, oxymorphone, and benzodiazepines in oral fluid compared to urine. The authors conclude that, overall, oral fluid tests produced comparable results to urine tests with some minor differences in detection rates for different drug classes. Introduction Acute and chronic pain are widespread and leading causes for physician visits. As physicians seek to ensure availability of appropriate medications for pain patients with legitimate medical needs, they concurrently attempt to minimize the risk of misuse, addiction, and diversion of the medications (1, 2). The role of toxicology testing in the management of chronic pain therapy has been the subject of numerous studies (3 5), and many health care specialists now utilize urine drug testing as a prominent component of patient assessment and compliance with drug treatment. Although physicians may rely upon observation and patient self-reports, urine tests provide objective diagnostic data that can effectively identify recent drug use patterns. For pain management, a properly conducted drug test identifies recent use of prescribed, non-prescribed, and illicit drugs. The absence of a prescribed drug merits discussion with the patient, whereas the presence of a non-prescribed or illicit drug evokes concerns regarding safety and may suggest the possibility of a coexisting disorder such as addiction (6). Historically, urine has been the matrix of choice for most drug testing programs, but advances in analytical technology and the introduction of commercial oral fluid assays have effectively established oral fluid as a viable alternative. Oral fluid (saliva) testing for drugs offers some advantages as a test matrix over urine. Collection can be performed in almost any location, under direct observation, and with reduced risk of adulteration or substitution. Drugs generally appear in oral fluid by passive diffusion from blood, but also may be deposited in the oral cavity during oral, smoked, and intranasal administration (7). Drug metabolites can also be detected in oral fluid. Unlike urine, there may be a close relationship between drug concentrations in oral fluid and the unbound fraction in plasma, but only in some cases are correlations between oral fluid and plasma significant (8, 9). However, detection of drugs or metabolites in oral fluid provides strong evidence for recent use. The development of oral fluid tests has engendered the publication of a significant body of scientific literature on a variety of aspects of oral fluid testing. Several reviews document aspects of oral fluid testing including drug disposition (10 12), detection times (13), diagnostics (14), legal issues (15), application of state-of-the-art technologies (16 21), and interpretation of results (7). Despite the advances in the use of oral fluid as a test matrix, there appears to be a paucity of information on comparison of test results from simultaneously collected oral fluid and urine specimens. Of the few studies reported, their primary focus has been use by criminal justice systems in screening individuals for illicit drug use (22, 23). This study compared oral fluid and urine drug test results in specimens collected in near simultaneous fashion from chronic pain patients undergoing therapeutic drug treatment. Specimens were analyzed for 42 drugs and/or metabolites by liquid chromatography tandem mass spectrometry (LC MS MS) procedures. For purposes of this study, test results for concentrations greater than or equal to the limits of quantitation (LOQ) in each sample matrix were compared. Materials and Methods Patients and specimen collection A total of 133 patients undergoing treatment for chronic pain at four clinics located in three states (FL, TN, and WV) provided informed consent and agreed to participate in the study. All patients were enrolled in pain management compliance monitoring programs that included urine drug testing for licit and illicit drugs. The study was approved by the Essex Institutional Review Board (Lebanon, NJ). Patients provided a # The Author [2012]. Published by Oxford University Press. All rights reserved. For Permissions, please journals.permissions@oup.com

2 urine specimen, then immediately collected two oral fluid specimens. Specimens were collected during the period from January 1, 2009, to February 28, 2009, and were shipped to Aegis Sciences (Nashville, TN) for analysis. Of the 133 specimen sets, analyses of different drug groups were limited to those requests by the treating physicians. The specimen sets underwent testing for all drug metabolite combinations offered by the laboratory with the exception of the following drug groups: buprenorphine/norbuprenorphine (93 sets of specimens were tested); cannabis (100 sets were tested); and tramadol (123 sets of specimens were tested). Oral fluid specimens were collected per manufacturer s instructions with Quantisal TM (Immunalysis, Pomona, CA) saliva collection devices. The Quantisal collection device consists of a cellulose pad affixed to a plastic stem with a volume adequacy indicator. The pad was placed under the tongue of an individual and remained there until the required volume of oral fluid (1 ml) had saturated the pad as evidenced by the indicator turning blue. After sufficient volume was collected, the pad was removed and placed into the transport tube containing 3 ml of buffer with preservative. The transport tube was capped, labeled, and stored at room temperature until shipment to the laboratory for analysis. Collection times were not monitored in this study. Laboratory analyses Oral fluid specimens were analyzed for a wide range of licit and illicit drugs by validated LC MS MS and previously published procedures (24). Drugs and metabolites detected in oral fluid and/or urine are listed in Table I along with their associated lower LOQ. Briefly, oral fluid specimens were prepared for analysis by either liquid liquid extraction (LLE) or solidphase extraction (SPE). For the LLE procedure, 500 ml of sample from the collection device was fortified with deuterated internal standards and extracted with a 1:4 mixture of hexane/ethyl acetate. The organic phase was separated and evaporated, and the residue was reconstituted with 200 ml of 10 mm ammonium acetate, 0.1% formic acid HPLC water (mobile phase). For SPE analysis, a GV-65 column (Biochemical Diagnostics, Edgewood, NY) was used. Oral fluid specimens were fortified with deuterated internal standards, mixed with 0.25 M phosphate buffer ( ph 6), and loaded onto a conditioned SPE column. The column was washed with deionized water, 0.01 M acetic acid, and methanol and then eluted with 1:1 acetone/chloroform. The organic eluate was evaporated, and the residue was reconstituted with 200 ml (50 ml for THC) of mobile phase. LC MS MS analyses were performed with an AB Sciex 4000 Q-trap MS and Shimadzu LC-20AD HPLC pumps. The mobile phase was 10 mm ammonium acetate, 0.1% formic acid HPLC water and 0.1% formic acid acetonitrile. The HPLC column was a Restek Pinnacle DB C 18 3 mm, mm. All analyses were performed with electrospray ionization ( positive or negative mode). Typical conditions for analysis were as follows: curtain gas, 30 psi; collision induced dissociation gas, 5 psi; heated nebulizer temperature, 6508C; gas 1, 70 psi; and gas 2, 65 psi. To identify the appropriate multiple reaction monitoring (MRM) transitions and analysis conditions for each compound, solutions of standards in methanol/water (50:50, v/v) were Table I LOQs for Drugs and Metabolites Measured in Oral Fluid and Urine Drug (Metabolite) Oral Fluid LC MS MS LOQs (ng/ml) Urine Confirmation LOQs (ng/ml) Alprazolam 0.5 NT (a-oh-alprazolam) NT* 50 Amphetamine 5 80 Buprenorphine (Norbuprenorphine) 2 2 Butalbital Carisoprodol (Meprobamate) Clonazepam 1 NT (7-Aminoclonazepam) NT 50 Cocaine 2 NT (Benzoylecgonine) 2 20 Codeine 1 50 Diazepam 1 NT (Nordiazepam) 1 50 (Oxazepam) (Temazepam) Fentanyl (Norfentanyl) Hydrocodone 1 50 (Hydromorphone) 1 50 (Norhydrocodone) 1 50 (Dihydrocodeine) 1 50 Hydromorphone 1 50 Lorazepam 1 50 Methadone 2 50 (EDDP) 1 50 Methamphetamine 8 80 Morphine 1 50 (Hydromorphone) 1 50 Oxycodone 1 50 (Oyxmorphone) 1 50 (Noroxycodone) 1 50 Propoxyphene 5 50 (Norpropoxyphene) 1 50 Temazepam (Oxazepam) Tetrahydrocannabinol 1 NT (THCCOOH) 2 2 Tramadol (N-Desmethyltramadol) (O-Desmethyltramadol) *NT¼ not tested. infused into the MS, and the declustering potential and collision energies were optimized for each compound. Data acquisition, peak integration, and calculations were performed using a computer workstation running Analyst software. Criteria for identification and measurement of analytes in oral fluid were as follows: the relative retention time (RRT) of each analyte in the donor sample was required to be within of its respective RRT in the calibrator or the retention time (RT) of each analyte in the sample was required to be within +3% of its respective RT in the calibrator; ion ratios for the product ions derived from analytes and internal standards in controls and donor specimens had to be within +20% of the mean range of the corresponding analytes in the calibrator; control sample concentrations had to measure within +20% of the in-house determined mean value; and negative controls could not contain analytes above the LOQ. The LOQ for each analyte was determined by serial dilution with oral fluid buffer (Immunalysis) of oral fluid samples fortified at known drug concentrations. The lowest concentration that could be accurately measured (+ 20% of target concentration) and met identification criteria was defined as the LOQ. The upper limit of 76 Heltsley et al.

3 linearity (ULOL) was defined as the maximum concentration that could be accurately measured (+ 20% of target concentration) and also met all identification criteria. Included in this report are all quantitative data for drugs and metabolites that met identification and quantitation ( LOQ) criteria. Analyte concentrations in oral fluid were adjusted for the fourfold dilution (1 ml oral fluid added to 3 ml buffer) with the Quantisal collection device in order to represent native oral fluid concentration. Accompanying urine specimens were initially screened by automated immunoassay procedures per manufacturer s instructions. The immunoassay test kits were obtained from the following manufacturers and utilized at the indicated cutoff concentrations (ng/ml): Microgenics (Fremont, CA) CEDIA w Amphetamines Assay (1000), DRI w Ecstasy Assay (250); CEDIA w Barbiturate Assay (200), CEDIA w Cocaine Assay (100), CEDIA w Methadone Metabolite (EDDP) Assay (200), CEDIA w Multi Level THC Assay (20), DRI w Oxycodone Assay (100), and CEDIA w Propoxyphene Assay (300) and Immunalysis Benzodiazepines ELISA Kit (100), Buprenorphine Direct ELISA Kit (1), Carisoprodol Direct ELISA Kit (200), Fentanyl ELISA Kit (1), Opiates Direct ELISA Kit (100), and Tramadol Direct ELISA Kit (Tramadol Specific) (100). Non-negative specimens were confirmed by MS according to published procedures (25 27). The analytes detected and measured in urine are listed in Table I along with their MS confirmation LOQs. Data analyses Mean, standard error of the mean (SEM), median, and concentration range data were determined for each analyte (. LOQ). To evaluate the validity of oral fluid drug detection, sensitivity, specificity, and percentage agreement (compared to urine as the reference point) along with Cohen s Kappa value were calculated. Based on the criteria suggested by Landis and Koch (28), Cohen s Kappa values were determined and evaluated as follows: value of less than 0 as poor, as slight, as fair, as moderate, as substantial, and as an almost perfect agreement. Results Prevalence and concentration The prevalence and concentration data for the 34 drugs/metabolites detected in oral fluid and/or urine specimens from the 133 pain patients are listed in Table II. In some instances, different analytes were tested in oral fluid compared to urine (alprazolam, clonazepam, and cannabis) and additional analytes were included in oral fluid assays (diazepam and cocaine). Oxycodone and its related metabolic products (noroxycodone and oxymorphone) were the most prevalently detected analytes in both oral fluid and urine, followed by hydrocodone (and related metabolites), morphine, benzodiazepines, carisoprodol, methadone, and fentanyl. In addition, evidence of cannabis use was identified in 6 oral fluid and 12 urine specimens. Cocaine use was evident in 9 oral fluid and 6 urine specimens. Generally, drug/metabolite concentrations in urine exceeded concentrations in oral fluid by 10- to 100-fold. As a measure of dependence between oral fluid and urine concentrations, Pearson product-moment correlation coefficients were derived for analyte concentrations for which the number of data sets was 10. Nine sets of analyte data (dihydrocodeine, r ¼ 0.81; EDDP, r ¼ 0.51; hydrocodone, r ¼ 0.69; meprobamate, r ¼ 0.19; morphine, r ¼ 0.54; norhydrocodone, r ¼ 0.41; noroxycodone, r ¼ 0.28; oxycodone, r ¼ 0.19; and oxymorphone, r ¼ 0.04) were examined. At an alpha level of.05, there was a significant relationship between oral fluid and urine concentrations for dihydrocodeine, hydrocodone, morphine, and noroxycodone. Figure 1 illustrates an example of the scatter plot and trend line for morphine concentrations in oral fluid and urine. Agreement between oral fluid and urine Comparison of LC MS MS results for oral fluid with those of urine specimens is shown in Table III. Of the 1544 paired tests, 329 (21.3%) drug analytes were positive and 984 (63.7%) were negative in both matrices for an overall agreement of 85%. There were 83 (5.4%) of the analyte results that were positive in oral fluid and negative in urine and 148 (9.6%) were negative in oral fluid and positive in urine for an overall disagreement of 15%. Validity, agreement, and predictive value were determined as statistical measures of intermatrix agreement for the detection of analytes in oral fluid versus urine (Table IV). Sensitivity and specificity of oral fluid, using urine as the reference point, represent the proportion of positive results and negative results in agreement, respectively. The overall sensitivity for the 1544 comparisons was 69.0%, and specificity was 92.2%. As stated earlier, the overall agreement was 85.0%, whereas the agreement expected by chance was 58.9%. Kappa values of 1 and 1 indicate perfect agreement and disagreement, respectively, and a Kappa of 0 indicates agreement equivalent to chance. The overall Kappa value for the entire set of tests was 0.64 and was judged by criteria suggested by Landis and Koch (28) as substantial agreement. Positive and negative predictive values are the proportion of samples with positive and negative tests that are correctly diagnosed, respectively. The overall positive and negative predictive values for the entire set of tests were 79.9% and 86.9%, respectively. Two subsets of these data were also evaluated in a similar manner. There were 263 comparisons for drugs (morphine, codeine, cannabinoids, cocaine, amphetamine, and methamphetamine) included in the federal workplace program by the Department of Health and Human Services (DHHS). The agreement and Kappa value for this set was 92.4% and 0.73, respectively. An extended DHHS set, which included hydrocodone and oxycodone (n ¼ 491 comparisons) was also evaluated. The agreement and Kappa value for this set was 89.2% and 0.74, respectively. Both subsets were rated as exhibiting substantial agreement in results between oral fluid and urine. Discussion This work evaluated the potential for oral fluid to be used as an alternative to urine for compliance monitoring of pain patients prescription and illicit drug use. Comparisons were made between the confirmed presence of drug and/or metabolite in Oral Fluid Drug Testing of Chronic Pain Patients. II. Comparison of Paired Oral Fluid and Urine Specimens 77

4 Table II Prevalence, Mean, Median, and Concentration Range of Drug and Metabolite Concentrations in Oral Fluid and Urine Specimens of 133 Pain Patients Oral Fluid (ng/ml) Urine (ng/ml) Drugs/Metabolites N Mean + SEM Median Range Drugs/Metabolites N Mean + SEM Median Range Amphetamines Amphetamine Amphetamine Methamphetamine Methamphetamine ND* Benzodiazepines Alprazolam a-oh-alprazolam Clonazepam Aminoclonazepam Diazepam Diazepam NT Lorazepam Lorazepam ND Nordiazepam Nordiazepam Oxazepam Oxazepam Temazepam Temazepam Cannabis THC THCCOOH Carisoprodol Carisoprodol Carisoprodol Meprobamate Meprobamate Cocaine Benzoylecgonine Benzoylecgonine Cocaine Cocaine NT Opiates Codeine Codeine ND Norcodeine ND Norcodeine Morphine Morphine Hydrocodone Hydrocodone Norhydrocodone Norhydrocodone Dihydrocodeine Dihydrocodeine Hydromorphone Hydromorphone Oxycodone Oxycodone Noroxycodone Noroxycodone Oxymorphone Oxymorphone Opioids Buprenorphine Buprenorphine 1 3 Norbuprenorphine Norbuprenorphine Fentanyl Fentanyl Norfentanyl Norfentanyl Methadone Methadone EDDP EDDP Propoxyphene Propoxyphene Norpropoxyphene Norpropoxyphene Tramadol N-Desmethyltramadol N-Desmethyltramadol ND O-Desmethyltramadol ND O-Desmethyltramadol * Abbreviations: NT ¼ not tested; ND ¼ not detected. The number of oral fluid/urine sets for these drug groups was limited by the prescribing physician as follows: buprenorphine/norbuprenorphine, n ¼ 93 sets; cannabis, n ¼ 100 sets; and tramadol, n ¼ 123. Figure 1. Scatter plot and trend line of oral fluid and urine concentrations (ng/ml) of morphine. oral fluid and urine at concentrations LOQ of the MS assay. Urine specimens were initially screened by immunoassay and only presumptive positive results were submitted for confirmation analyses. All oral fluid specimens were analyzed directly by LC MS MS. A variety of assays for drugs in oral fluid have been reported (21, 29, 30) and some have proposed use of LC MS MS for direct analysis without prior immunoassay screening (19, 31). This approach was taken for oral fluid specimens in the current study; however, it is acknowledged that such comparisons are influenced by the sensitivity and performance characteristics of the individual immunoassay tests used for urine screening. Generally, there was good agreement in analyte test results between oral fluid and urine (85% of specimen sets tested either positive/positive or negative/negative). The overall discordant results between oral fluid and urine was 15%, of which 5.4% were positive in oral fluid and negative in urine and 9.6% were positive in urine and negative in oral fluid. One possible 78 Heltsley et al.

5 explanation for discordant results could be the result of difference in time course of drugs and metabolites in these two matrices. Those specimens that were positive in oral fluid and negative in urine possibly occurred as a result of early appearance of drug in oral fluid before there was sufficient time for metabolism and urinary excretion. For example, Niedbala et al. (32) reported higher positivity rates for oral fluid from cannabis smokers over the first 8 h after smoking than in urine. The authors suggested this finding was due to the time lag imposed Table III Test Agreement Between Oral Fluid and Urine Drug/Metabolite Positive and Urine Positive Positive and Urine Negative Negative and Urine Positive Amphetamine Methamphetamine a-oh-alprazolam (U)/ Alprazolam (OF)* 7-Aminoclonazepam (U)/Clonazepam (OF) Negative and Urine Negative Lorazepam Nordiazepam Oxazepam Temazepam THCCOOH (U)/THC (OF) Carisoprodol Meprobamate Benzoylecgonine Codeine Norcodeine Morphine Hydrocodone Norhydrocodone Dihydrocodeine Hydromorphone Oxycodone Noroxycodone Oxymorphone Buprenorphine Norbuprenorphine Fentanyl Norfentanyl Methadone EDDP Propoxyphene Norpropoxyphene Tramadol N-Desmethyltramadol O-Desmethyltramadol Total 329 (21.3%) 83 (5.4%) 148 (9.6%) 984 (63.7%) * Abbreviations: U, urine; OF, oral fluid. by the need for sufficient parent drug (tetrahydocannabinol) to be metabolized and subsequently excreted in urine. Conversely, longer detection times for drugs and metabolites in urine compared to oral fluid likely account for those specimens that tested positive in urine and negative in oral fluid. Some analytes exhibited higher rates of discordance. The primary examples of these include hydromorphone and oxymorphone, which had lower detection rates in oral fluid compared to urine. The greater polar nature and lower lipophilicity of these analytes relative to the parent drugs, hydrocodone and oxycodone, would reduce their transfer from blood to oral fluid and likely contributed to their lower detection rates in oral fluid. Qualitatively, the benzodiazepines also appeared to be detected less frequently in oral fluid compared to urine. Because of the weakly acidic nature of benzodiazepines and extensive binding to plasma proteins (33), their concentrations in oral fluid tend to be quite low, thus making these drugs difficult to detect. An earlier study comparing oral fluid (collected with a Salivette w device consisting of a cotton roll) with urine for detection of benzodiazepines in drivers stopped during a roadside survey reported that 27 urine specimens tested positive for benzodiazepines, of which only 5 oral fluid specimens were positive (34). In comparison, the current results are more favorable for detection of the benzodiazepines in oral fluid, but still tended to identify fewer positive specimens. Although concentrations of analytes in oral fluid, as expected, were considerably lower than in urine, regression analyses for some analytes (dihydrocodeine, hydrocodone, morphine, and noroxycodone) yielded significant results. Despite these findings, there was considerable scatter of these data, as illustrated for the morphine results in Figure 1, precluding the use of oral fluid as predictor of urine concentrations. In the pain management setting, information from drug tests also provides information on patients use of illicit drugs. Detection of illicit drug use could signal that the patient needs assessment for possible addictive disorders. In the current study, 6 patients tested positive for cannabis in oral fluid tests and 12 were positive in urine tests. In contrast, 9 patient samples were positive for cocaine in oral fluid compared to 6 in urine. Similar findings of illicit drug use have been reported in earlier studies of chronic pain patients undergoing compliance testing with oral fluid (24) and urine (25). In conclusion, analyses of oral fluid and urine specimens collected from chronic pain patients in a concurrent fashion Table IV Validity, Intermatrix Agreement, and Predictive Value of Oral Fluid Compared to Urine as a Gold Standard Validity Agreement Predictive Value Specimen Drug Set # Comparisons Sensitivity Specificity Agreement Agreement Expected by Chance Cohen s Kappa Strength of Agreement* Positive Negative DHHS (4 drug Substantial categories) ( ) ( ) ( ) ( ) ( ) DHHS (Extended) Substantial ( ) ( ) ( ) ( ) ( ) All drugs Substantial ( ) ( ) ( ) ( ) ( ) * Based on the criteria suggested by Landis and Koch (28) for Cohen s Kappa values. DHHS (4 drug categories) include amphetamines, cannabis, cocaine, and opiates); DHHS (Extended) includes the 4 drug categories plus hydrocodone and oxycodone. Values in parentheses are 95% confidence intervals. Oral Fluid Drug Testing of Chronic Pain Patients. II. Comparison of Paired Oral Fluid and Urine Specimens 79

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