Drugs in Sweat.

N. Samyn, G. De Boeck and A. G. Verstraete (2002). “The use of oral fluid and sweat wipes for the detection of drugs of abuse in drivers.” Journal of Forensic Sciences 47(6): 1380-7.

            Blood, urine, oral fluid (by spitting or with a Salivette), and sweat samples (by wiping the forehead with a fleece moistened with isopropanol) were obtained from 180 drivers who failed the field sobriety tests at police roadblocks. With quantitative GC-MS, the positive predictive value of oral fluid was 98, 92, and 90% for amphetamines, cocaine, and cannabis respectively. The prevalence of opiate positives was low. The proposed SAMHSA cut-off values for oral fluid testing at the workplace, proved their usefulness in this study. The positive predictive value of sweat wipe analysis with GC-MS was over 90% for cocaine and amphetamines and 80% for cannabis. The accuracy of Drugwipe was assessed by comparing the electronic read-out values obtained on-site after wiping the tongue and the forehead, with the corresponding GC-MS results in plasma, oral fluid, and sweat. The accuracy was always less than 90% except for the amphetamine-group in sweat.

O. Y. Al-Dirbashi, K. Ikeda, M. Takahashi, N. Kuroda, S. Ikeda and K. Nakashima (2001). “Drugs of abuse in a non-conventional sample; detection of methamphetamine and its main metabolite, amphetamine in abusers' clothes by HPLC with UV and fluorescence detection.” Biomedical Chrmatography 15(7): 457-63.

            In this paper, we report the detection of methamphetamine and its major metabolite, amphetamine, in garments belong to known-abusers. These compounds were extracted from the textile using a mixture of chloroform:propan-2-ol (3:1, v/v), derivatized with 4-(4,5-diphenyl-1H-imidazol-2-yl) benzoyl chloride and separated using a reversed-phase high-performance liquid chromatography. The derivatives were detected by measuring either fluorescence at 440 nm or absorbance at 330 nm. By using 1-methyl-3-phenyl propylamine as an internal standard, calibration curves of spiked textile samples were linear over a wide range with correlation coefficients of 0.997 or better. Detection limits at a signal-to-noise ratio of 3 were less than or equal to 37.3 and 0.4 pg on column for the high-performance liquid chromatography-ultraviolet and -fluorescence detection methods, respectively. Intra- and inter-day variations at high and low concentrations (n > or = 3) were < or =12.7%. The developed methods were successfully applied to the determination of methamphetamine and amphetamine in clothes samples belong to abusers. Copyright 2001 John Wiley & Sons, Ltd.

D. J. Crouch, R. F. Cook, J. V. Trudeau, D. C. Dove, J. J. Robinson, H. L. Webster and A. A. Fatah (2001). “The detection of drugs of abuse in liquid perspiration.” Journal of Analytical Toxicology 25(7): 625-7.

D. E. Moody and M. L. Cheever (2001). “Evaluation of immunoassays for semiquantitative detection of cocaine and metabolites or heroin and metabolites in extracts of sweat patches.” Journal of Analytical Toxicology 25(3): 190-7.

            Two types of immunoassays, radioimmunoassay (RIA) and microplate enzyme immunoassay (EIA), were compared for their ability to detect and quantitate cocaine and metabolites or heroin and metabolites in extracts of sweat patches. Experiments used sweat patches that had been fortified with cocaine, benzoylecgonine (BE), and ecgonine methyl ester (EME) or 6-acetylmorphine (6-AM), heroin, and morphine. Assays were first evaluated for sensitivity in detection of the analyte(s) known to be excreted in sweat (cocaine >> BE and EME; 6-AM > heroin > morphine). The cocaine metabolite RIA had cross-reactivity for cocaine > BE > EME, and the cocaine metabolite EIA had cross-reactivity for BE > cocaine >> EME. The RIA, having greater sensitivity for COC, was studied further. Optimal linearity was 4 to 200 ng/patch, and quantitation within these limits at 4, 75, and 150 ng/patch had intrarun %CVs within 7.8% and percent targets within 15% and inter-run %CVs within 13.5% and % targets within 13%. The opiate RIA had cross-reactivities for morphine >> 6-AM and heroin. The opiate EIA had cross-reactivities for 6-AM and heroin of 42 and 28% relative to morphine, respectively. The EIA, having greater sensitivity for 6-AM and heroin, was studied further. The limits of detection ranged from 1.7 to 24.7 ng/patch, and the lower limits of quantitation ranged from 7.3 ng/patch to beyond the linear range. The assay, however, had consistently good precision at 4 and 5 ng/patch, and optimal linearity was established from 4 to 100 ng/patch. With controls at 5, 25, and 90 ng/patch, both intrarun and inter-run precision were acceptable. Quantitation was accurate at 5 and 25 ng/patch, but the 90 ng/patch controls were consistently < 70% of target. Because our studies focused on the assays that had greater sensitivity for the analytes excreted in sweat, we did not fully evaluate the cocaine metabolite EIA or the RIA opiate screen and therefore cannot make any comment on the usefulness of these assays for detecting analytes in extracts of sweat patches beyond predicting that they will have less sensitivity. Both the cocaine metabolite RIA and opiate EIA had the ability to detect analytes known to be extracted from sweat patches.

R. Pacifici, M. Farre, S. Pichini, J. Ortuno, P. N. Roset, P. Zuccaro, J. Segura and R. de la Torre (2001). “Sweat testing of MDMA with the Drugwipe analytical device: a controlled study with two volunteers.” Journal of Analytical Toxicology 25(2): 144-6.

            Rapid on-site tests for the analysis of drugs of abuse in unconventional specimens (e.g., sweat) have recently been developed. Two healthy volunteers familiar with the effects of methylenedioxymethamphetamine (MDMA) were given 100 mg of the drug as a single oral dose. MDMA and its main metabolite 4-hydroxy-3-methoxymethamphetamine (HMMA) were determined in plasma and urine by gas chromatography-mass spectrometry (GC-MS). MDMA was also investigated in sweat with the Drugwipe (an immunochemical strip test). Subjects' armpits were swabbed for 10 s at 0 time (predose) and at 2, 6, 8, 12, and 24 h after MDMA administration. MDMA consumption could be detected using Drugwipe at 2 h and for as long as 12 h after drug administration. However, in one of the volunteers, a faint color change appeared at 0 time, when plasma and urine tested negative for MDMA and did not disappear even 48 h later. Plasma concentrations of MDMA and HMMA measured by GC-MS peaked at 2-4 h, and values greater than 20 ng/mL for MDMA and of 40 ng/mL for HMMA were still detected at 24 h. Urine tested positive by GC-MS for MDMA and HMMA in the 48-h collection period. These findings preliminarily support sweat testing with Drugwipe for monitoring MDMA use.

Y. H. Caplan and B. A. Goldberger (2001). “Alternative specimens for workplace drug testing.” Journal of Analytical Toxicology 25(5): 396-9.

            Recent advances in analytical techniques have enabled the detection of drugs and drug metabolites in alternative biological specimens for the purposes of workplace testing. A wide variety of specimens are available, each providing valuable information concerning prior or current drug use. The present focus is on oral fluid (saliva), hair, and sweat. An extensive evaluation by the Division of Workplace Programs of the Department of Health and Human Services is underway to determine the utility of these specimens in federally regulated programs. In future years, the testing of alternative specimens will expand our ability to understand the patterns of drug use and will become routine in all areas of forensic toxicology. [References: 6]

D. A. Kidwell and F. P. Smith (2001). “Susceptibility of PharmChek drugs of abuse patch to environmental contamination.” Forensic Science International. 116(2-3): 89-106.

            The key component of the PharmChek sweat patch, the membrane, has been tested for the passage of externally applied materials. Drugs in the uncharged state rapidly penetrated the membrane but charged species were greatly slowed. In basic media, detectable concentrations of cocaine, methamphetamine, and heroin were observed at the earliest collection time (ca. 30 s), after drugs were placed on the outside of the membrane. Drug concentrations increased over the 2 h time course, when amounts detected (1710 ng cocaine, 1060 ng methamphetamine, 550 ng heroin per pad at 2 h) represented 5-17% of the drug deposited on the surface of the sweat patch.Drugs externally applied to human skin were shown to bind readily. Drugs deposited on the skin of drug-free volunteers several days prior to application of the sweat patch were not completely removed by normal hygiene or the cleaning procedures recommended before application of the sweat patch. Even 6 days of normal hygiene did not remove all drugs from externally contaminated skin and positive sweat patches resulted. A mechanism for passage of drugs through the sweat patch membrane, a mechanism for retention of drugs on skin, and a redesign of the sweat patch and modification of its use to reduce external contamination are proposed. Appropriate care should be taken in the interpretation of positive results from a sweat patch test until more research is conducted.

V. Spiehler (2000 Jan 10). “Hair analysis by immunological methods from the beginning to 2000.” Forensic Science International. 107(1-3): 249-59.

            Immunoassays for hair testing must satisfy three requirements: (1) They must have cross-reactivity with parent drug and lipophilic metabolites actually found in hair (2) they must not experience interference from the dissolved hair matrix and (3) they must be titered for cutoffs appropriate to the drug concentrations found in hair. Because the analytes found in hair after drug use are generally the parent drug or its lipophilic metabolites, immunoassays developed and intended for urine testing are not suitable for hair. Immunoassays whose antibodies are bound to a solid support, such as coated-tube radioimmunoassay or coated-plate ELISA tests, experience less matrix interference than those which use other means of separation of bound and free fractions. Homogenous assays are not suitable for hair testing because the hair matrix frequently interferes in the detection of the signal. Historically radioimmunoassays for drugs of abuse were first used for detecting drugs in hair. Currently ELISAs and coated-plate 96 well microplate EIAs are employed for screening hair digests or extracts for drugs. The optimum cutoffs for immunoassays for drugs in hair should be chosen based on the analyte concentration which produces the fewest false positive or false negative results when applied to tests of hair from known users and non-users of drugs. A hair immunoassay test at these cutoffs should have a sensitivity and specificity of better than 90%. The predictive value of the test will depend on the prevalence of drug use in the tested population. Cutoffs or decision thresholds for immunoassays used for screening for drugs should not be at the limit of detection of the assay because that produces a very large incidence of false positives. Because immunoassays are ligand-binding assays, they have a short range of linearity with low precision at both ends of the range. In the future, immunoassays will continue to be used for screening hair and other matrices for drugs of abuse because they provide rapid, inexpensive automated procedures for separating negative specimens from those which are suspected of containing drugs. For forensic purposes, all positive results must be confirmed by an independent analysis using a procedure based on a different property of the analyte. An immunoassay test should not be confirmed by a second immunoassay test but by a chromatographic test performed on a different dissolved or extracted aliquot of the original specimen. [References: 24]

M. A. Huestis, E. J. Cone, C. J. Wong, A. Umbricht and K. L. Preston (2000). “Monitoring opiate use in substance abuse treatment patients with sweat and urine drug testing.” Journal  of Analytical Toxicology 24(7): 509-21.

            Although urine testing remains the standard for drug use monitoring, sweat testing for drugs of abuse is increasing, especially in criminal justice programs. One reason for this increase is sweat testing may widen the detection window compared to urine testing. Drug metabolites are rapidly excreted in urine limiting the window of detection of a single use to a few days. In contrast, sweat collection devices can be worn for longer periods of time. This study was designed to compare the efficacy of sweat testing versus urine testing for detecting drug use. Paired sweat patches that were applied and removed weekly on Tuesdays were compared to 3-5 consecutive urine specimens collected Mondays, Wednesdays, and Fridays (355 matched sweat and urine specimen sets) from 44 patients in a methadone-maintenance outpatient treatment program. All patches (N = 925) were extracted in 2.5 mL of solvent and analyzed by ELISA immunoassay for opiates (cutoff concentration 10 ng/mL). A subset (N = 389) of patches was analyzed by gas chromatography-mass spectrometry (GC-MS). Urine specimens (N = 1886) were subjected to qualitative analysis by EMIT (cutoff 300 ng/mL). Results were evaluated to (1) determine the identity and relative amounts of opiates in sweat; (2) assess replicability in duplicate patches; (3) compare ELISA and GC-MS results for opiates in sweat; and (4) compare the detection of opiate use by sweat and urine testing. Opiates were detected in 38.5% of the sweat patches with the ELISA screen. GC-MS analysis confirmed 83.4% of the screen-positive sweat patches for heroin, 6-acetylmorphine, morphine, and/or codeine (cutoff concentration 5 ng/mL) and 90.2% of the screen-negative patches. The sensitivity, specificity, and efficiency of ELISA opiate results as compared to GC-MS results in sweat were 96.7%, 72.2%, and 89.5%, respectively. Heroin and/or 6-acetylmorphine were detected in 78.1% of the GC-MS-positive sweat patches. Median concentrations of heroin, 6-acetylmorphine, morphine, and codeine in the positive sweat samples were 10.5, 13.6, 15.9, and 13.0 ng/mL, respectively. Agreement in paired sweat patch test results was 90.6% by ELISA analysis. For the purposes of this comparison of ELISA sweat patch to EMIT urine screening for opiates, the more commonly used urine test was considered to be the reference method. The sensitivity, specificity, and efficiency of sweat patch results to urine results for opiates were 68.6%, 86.1%, and 78.6%, respectively. There were 13.5% false-negative and 7.9% false-positive sweat results as compared to urine tests. Analysis of sweat patches provides an alternate method for objectively monitoring drug use and provides an advantage over urine drug testing by extending drug detection times to one week or longer. In addition, identification of heroin and/or 6-acetylmorphine in sweat patches confirmed the use of heroin in 78.1% of the positive cases and differentiated illicit heroin use from possible ingestion of codeine or opiate-containing foods. However, the percentage of false-negative results, at least in this treatment population, indicates that weekly sweat testing may be less sensitive than thrice weekly urine testing in detecting opiate use.

L. Rivier (2000). “Techniques for analytical testing of unconventional samples.” Best Practice & Research Clinical Endocrinology & Metabolism. 14(1): 147-65.

            Forensic scientists have long detected the presence of drugs and their metabolites in biological materials using body fluids such as urine, blood and/or other biological liquids or tissues. For doping analysis, only urine has so far been collected. In recent years, remarkable advances in sensitive analytical techniques have encouraged the analysis of drugs in unconventional biological samples such as hair, saliva and sweat. These samples are easily collected, although drug levels are often lower than the corresponding levels in urine or blood. This chapter reviews recent studies in the detection of doping agents in hair, saliva and sweat. Sampling, analytical procedures and interpretation of the results are discussed in comparison with those obtained from urine and blood samples. [References: 76]

N. Samyn and C. van Haeren (2000). “On-site testing of saliva and sweat with Drugwipe and determination of concentrations of drugs of abuse in saliva, plasma and urine of suspected users.” International Journal of Legal Medicine. 113(3): 150-4.

            Potential drug users participated voluntarily in a Belgian study on the usefulness of the non-instrumental immunoassay Drugwipe (Securetec, Germany) for the screening of cocaine, opiates, amphetamine and cannabinoids in saliva and sweat. If one of the screening assays (urine, oral fluid, sweat) showed a positive result, blood and saliva were collected. The on-site Drugwipe results were correlated with the Drugwipe results for saliva in the laboratory and with the GC/MS results of the corresponding saliva, plasma and urine samples and pharmacological effects at the time of sampling. The Drugwipe assay proved to be sufficiently sensitive for the detection of recent cocaine (n = 6) and amphetamine (n = 15) abuse, whether the device was wiped on the tongue or on the surface of the body, or when a saliva sample was applied to the wiping part. In five of the six potential cocaine users, the saliva concentrations of cocaine exceeded 1,000 ng/ml. In the amphetamine group, the saliva concentrations of amphetamine, MDMA or both were high (> 1,000 ng/ml) in 13 subjects. For cocaine and amphetamine, the positive scores for Drugwipe matched the GC/MS results for the three body fluids. Recent heroin abuse (n = 5) could be demonstrated to some extent with Drugwipe on samples from the tongue but only the two subjects with the highest saliva concentrations of MAM (> 500 ng/ml) and morphine (> 500 ng/ml) were positive. If the legal cut-off value for driving under the influence of opiates in Belgium (20 ng/ml of free morphine in plasma) was taken into account, only three subjects would have been legally positive. For cannabinoids (n = 15), false negatives and even some false positives were observed. Saliva can be considered as a useful analytical matrix for the detection of drugs of abuse after recent abuse when analysed with GC/MS.

J. A. Levisky, D. L. Bowerman, W. W. Jenkins and S. B. Karch (2000). “Drug deposition in adipose tissue and skin: evidence for an alternative source of positive sweat patch tests.” Forensic Science International. 110(1): 35-46.

            In a series of licit and illicit drug-related deaths, qualitative and quantitative analyses on extracts of adipose tissue and skin were performed by GC/MS. In all cases, the adipose tissue was found to contain drugs at concentrations lower than, approximately equal to, or even greater than the concentrations of the same analytes found in the blood, which may reflect a consequence of long-term chronic exposure, or acute intoxication, or some combination of both. Approximately one cubic inch of skin with adipose tissue was removed from the mid to lower abdominal region adjacent to the midline incision during autopsy. The drugs were recovered from the specimens following incubation and alkaline, acidic, and alkaline chloroform back extraction of one to three grams of tissue. Deuterated analogs of the analytes were added to the matrix at the beginning of the incubation period. Cocaine and free morphine (from heroin) were readily identified in several cases. The presence of these illicit drugs in adipose tissue raises significant forensic questions, especially the use of 'sweat patches' to monitor recent cocaine or heroin use in chronic drug users.

P. Kintz, V. Cirimele and B. Ludes (2000). “Detection of cannabis in oral fluid (saliva) and forehead wipes (sweat) from impaired drivers.” Journal  of Analytical Toxicology 24(7): 557-61.

            Saliva and sweat have been presented as two alternative matrices for the establishment of drug abuse. The noninvasive collection of a saliva or sweat sample, which is relatively easy to perform and can be achieved under close supervision, is one of the most important benefits in a driving-under-the-influence situation. Moreover, the presence of certain analytes in saliva is a better indication of recent use than when the drug is detected in urine, so there is a higher probability that the subject is experiencing pharmacological effects at the time of sampling. We developed an original procedure using gas chromatography-mass spectrometry to test for delta9-tetrahydrocannabinol (THC), the psychoactive ingredient of cannabis, in oral fluid and forehead wipes, collected with Sarstedt Salivettes and cosmetic pads, respectively. Blood, urine, oral fluid, and forehead wipes were simultaneously collected from 198 injured drivers admitted to an Emergency Hospital in Strasbourg, France. Of the 22 subjects positive for 11-nor-9-carboxy-THC (THCCOOH) in urine, 14 and 16 were positive for THC in oral fluid (1 to 103 ng/Salivette) and forehead wipe (4 to 152 ng/pad), respectively. 11-Hydroxy-THC and THCCOOH were not detected in these body fluids. Two main limitations of saliva and sweat are apparent: the amount of matrix collected is smaller when compared to urine, and the levels of drugs are higher in urine than in saliva and sweat. A current limitation in the use of these specimens for roadside testing is the absence of a suitable immunoassay that detects the parent compound in sufficiently low concentrations.

D. E. Moody (2000). “Units for sweat patch results.[comment].” Journal  of Analytical Toxicology 24(8): 733.

R. E. Joseph, Jr., K. M. Hold, D. G. Wilkins, D. E. Rollins and E. J. Cone (1999). “Drug testing with alternative matrices II. Mechanisms of cocaine and codeine deposition in hair.” Journal of Analytical Toxicology. 23(6): 396-408.

            A 10-week inpatient study was performed to evaluate cocaine, codeine, and metabolite disposition in biological matrices collected from volunteers. An initial report described drug disposition in plasma, sebum, and stratum corneum collected from five African-American males. This report focuses on drug disposition in hair and sweat collected from the same five subjects. Following a three-week washout period, three doses of cocaine HCl (75 mg/70 kg, subcutaneous) and three doses of codeine SO4 (60 mg/70 kg, oral) were administered on alternating days in week 4 (low-dose week). The same dosing sequence was repeated in week 8 with doubled doses (high-dose week). Hair was collected by shaving the entire scalp once each week. Hair from the anterior vertex was divided into two portions. One portion was washed with isopropanol and phosphate buffer; the other portion was not washed. Hair was enzymatically digested, samples were centrifuged, and the supernatant was collected. Sweat was collected periodically by placing PharmChek sweat patches on the torso. Drugs were extracted from sweat patches with methanol/0.2 M sodium acetate buffer (75:25, v/v). Supernatants from hair digests, hair washes, and sweat patch extracts were processed by solid-phase extraction followed by gas chromatography-mass spectrometry analysis for cocaine, codeine, 6-acetylmorphine, and metabolites. Cocaine and codeine were the primary analytes identified in sweat patches and hair. Drugs were detected in sweat within 8 h after dosing, and drug secretion primarily occurred within 24 h after dosing. No clear relationship was observed between dose and drug concentrations in sweat. Drug incorporation into hair appeared to be dose-dependent. Drugs were detected in hair within 1-3 days after the last drug administration; peak drug concentrations generally occurred in the following 1-2 weeks; thereafter, drug concentrations decreased. Solvent washes removed 50-55% of cocaine and codeine from hair collected 1-3 days after the last drug dose. These data may reflect removal of drug that was deposited by sweat shortly after dosing. Drug removed by washing hair collected 1-3 weeks after the last dose was minimal for cocaine but variable for codeine. Drug in these specimens was likely transferred from blood to germinative hair cells followed by emergence of drug in growing hair. These findings suggest that drug deposition in hair occurs by multiple mechanisms.

K. L. Preston, M. A. Huestis, C. J. Wong, A. Umbricht, B. A. Goldberger and E. J. Cone (1999). “Monitoring cocaine use in substance-abuse-treatment patients by sweat and urine testing.[comment].” Journal of Analytical Toxicology. 23(5): 313-22.

            Sweat and urine specimens were collected from 44 methadone-maintenance patients to evaluate the use of sweat testing to monitor cocaine use. Paired sweat patches that were applied and removed weekly (on Tuesdays) were compared with 3-5 consecutive urine specimens collected Mondays, Wednesdays, and Fridays. All patches (N = 930) were extracted in 2.5 mL of solvent and analyzed by ELISA immunoassay (cutoff concentration 10 ng/mL); a subset of patches (N = 591) was also analyzed by gas chromatography-mass spectrometry (GC-MS) for cocaine, benzoylecgonine (BZE), and ecgonine methyl ester (EME) (cutoff concentration 5 ng/mL). Urine specimens were subjected to qualitative analysis by EMIT (cutoff 300 ng/mL) and subsets were analyzed by TDx (semiquantitative, LOD 30 ng/mL) and by GC-MS for cocaine (LOD 5 ng/mL). Results were evaluated to (1) determine the relative amounts of cocaine and its metabolites in sweat; (2) assess replicability in duplicate patches; (3) compare ELISA and GC-MS results for cocaine in sweat; and (4) compare the detection of cocaine use by sweat and urine testing. Cocaine was detected by GC-MS in 99% of ELISA-positive sweat patches; median concentrations of cocaine, BZE, and EME were 378, 78.7, and 74 ng/mL, respectively. Agreement in duplicate patches was approximately 90% by ELISA analysis. The sensitivity, specificity, and efficiency of sweat ELISA cocaine results as compared with sweat GC-MS results were 93.6%, 91.3%, and 93.2%, respectively. The sensitivity, specificity, and efficiency between ELISA sweat patch and EMIT urine results were 97.6%, 60.5%, and 77.7%, respectively. These results support the use of sweat patches for monitoring cocaine use, though further evaluation is needed.

G. Skopp and L. Potsch (1999). “Perspiration versus saliva--basic aspects concerning their use in roadside drug testing.” International Journal of Legal Medicine. 112(4): 213-21.

            Various aspects concerning the practical application and forensic interpretation of data obtained by saliva drug testing and drug monitoring from the skin surface are discussed. Basic information on the composition of saliva and skin secretions and their particular transport mechanisms, as far as known, are given. For drugs of abuse secretion into saliva is suggested to be by passive diffusion and to depend on lipid solubility, pKa, plasma protein binding and on the pH of saliva. Drug molecules from blood are considered to reach the skin surface by various routes such as by sweat and sebum as well as by inter- and/or transcellular diffusion. The role of the stratum corneum as a temporary drug reservoir exceeding positive drug findings in urine is outlined. Current data on opioids, cocaine metabolites, cannabinoids and amphetamines detected in saliva and on the skin surface are reviewed. Aspects of collection, processing and analysis of the samples for implementation in roadside testing are addressed. The requirement of test sensitivity covering the broad concentration ranges and the importance of test specificity bearing in mind that the parent drug is the main analyte present in those specimens is stressed. Theoretical and practical findings on frequently abused drugs are discussed with regard to the possibilities and limitations of drug monitoring from saliva and perspiration to support a suspicion of actual or recent drug administration. [References: 74]

D. A. Kidwell, J. C. Holland and S. Athanaselis (1998). “Testing for drugs of abuse in saliva and sweat.[erratum appears in J Chromatogr B Biomed Sci Appl 1999 Jan 22;721(2):333].” Journal of Chromatography. B, Biomedical Sciences & Applications 713(1): 111-35.

            The detection of marijuana, cocaine, opiates, amphetamines, benzodiazepines, barbiturates, PCP, alcohol and nicotine in saliva and sweat is reviewed, with emphasis on forensic applications. The short window of detection and lower levels of drugs present compared to levels found in urine limits the applications of sweat and saliva screening for drug use determination. However, these matrices may be applicable for use in driving while intoxicated and surveying populations for illicit drug use. Although not an illicit drug, the detection of ethanol is reviewed because of its importance in driving under the influence. Only with alcohol may saliva be used to estimate blood levels and the degree of impairment because of the problems with oral contamination and drug concentrations varying depending upon how the saliva is obtained. The detection of nicotine and cotinine (from smoking tobacco) is also covered because of its use in life insurance screening and surveying for passive exposure. [References: 217]

P. Kintz, V. Cirimele and B. Ludes (1998). “Codeine testing in sweat and saliva with the Drugwipe.” International Journal of Legal Medicine 111(2): 82-4.

            With the growing interest in drug testing within different sectors of society, there has become a need for drug assays that can be performed immediately at the site of specimen collection. Recently, Securetec (Ottobrunn, Germany) has introduced the Drugwipe, a non instrument-based, on-site immunodiagnostic assay for the detection of drugs on surfaces. Different tests are available for opiates, cocaine and cannabis. To document the applications of the Drugwipe "opiate" on human biological fluids, 60 mg codeine phosphate were orally administered to 6 subjects. First, sweat testing with the Drugwipe was studied. The wiping section of the kit was used to swab the forehead of the subjects for 10 s, at 1, 4, 9 and 24 h after codeine administration. At the same time, for each period, a sweat patch (Pharmchek, USA) was applied to the outer portion of the upper arm. Codeine was then quantified in the patch by GC/MS and the measured concentrations used as reference. In all subjects except one the Drugwipe tested positive for opiates, however with few false negative results. In the second part of the study, results of the Drugwipe were compared with those obtained by GC/MS for saliva. The tongue of the subjects was carefully wiped over a period 24 h, and at the same time a specimen of saliva collected. Although codeine could be detected using the Drugwipe, numerous false negative results were observed. Codeine tested positive by GC/MS but remained negative using the Drugwipe in several cases. This can be explained by a codeine concentration which was too low to show positive with the Drugwipe, interfering substances may be present in saliva or the sampling procedure is inadequate.

P. Kintz, A. Tracqui, C. Marzullo, A. Darreye, F. Tremeau, P. Greth and B. Ludes (1998). “Enantioselective analysis of methadone in sweat as monitored by liquid chromatography/ion spray-mass spectrometry.” Therapeutic Drug Monitoring 20(1): 35-40.

            In recent years, remarkable advances in sensitive analytical techniques have enabled the analysis of drugs in unconventional samples, such as sweat. In a study conducted during a methadone maintenance program, PharmChek sweat patches were applied to 20 subjects. The subjects were orally administered methadone in 1 dosage/day, and doses ranged from 80 to 100 mg. The sweat patch was applied 10 minutes before administration and removed 72 hours later just before a new administration of methadone. The absorbent pad was stored at -20 degrees C until analysis in plastic tubes. Methadone was extracted in 5 ml methanol in presence of 200 ng of racemic methadone-d3, used as internal standard. After a 30-minute agitation, the methanol solution was evaporated to dryness. Enantioselective separation of methadone was obtained using an alpha-1-acid glycoprotein column (100 x 4 mm ID) and liquid chromatography/ion spray-mass spectrometry. In all 20 specimens obtained from subjects under racemic methadone treatment, R- (the active form) and S-enantiomers of methadone were identified with the following concentrations: 26 to 1118 ng/patch for R-methadone and 28 to 1114 ng/patch for S-methadone. The ratio between R- and S-methadone was in the range of 0.72 to 2.66 and was higher than 1.00 in 15 samples. No correlation between the doses of methadone administered and the concentrations of methadone in sweat was observed.

D. S. Shearer, G. J. Baciewicz and T. C. Kwong (1998). “Drugs of abuse testing in a psychiatric outpatient service.” Clinics in Laboratory Medicine 18(4): 713-26.

            Drug testing of patients in a psychiatric outpatient service is an effective way to identify patients who relapse into renewed use of drugs of abuse and in monitoring the effectiveness of ongoing medical and psychological therapy. Most of this testing involves the analysis of urine specimens with immunoassays. Hair testing affords an alternative specimen matrix that is easy to obtain and not readily adulterated and offers the advantage of a wider surveillance window. Hair analysis is technically demanding, and the possibility of false-positives caused by environmental contamination renders it a controversial alternative. Sweat and saliva are potentially useful testing matrices, but their usefulness in clinical practice must await validation by additional clinical and laboratory experience. The correct interpretation of drug test results is predicated on knowing the performance characteristics of the analytical method, route of administration, and pharmacokinetics of the drug. All questionable positive results need confirmation testing to verify true positivity. [References: 100]

P. Kintz, R. Brenneisen, P. Bundeli and P. Mangin (1997). “Sweat testing for heroin and metabolites in a heroin maintenance program.” Clinical Chemistry 43(5): 736-9.

            Recent advances in sensitive analytical techniques have enabled the analysis of drugs in unconventional biological materials such as sweat. In a study conducted during a heroin maintenance program, 14 subjects had sweat patches applied, then received intravenously two or three doses of heroin hydrochloride ranging from 80 to 1000 mg/day. The sweat patch was applied 10 min before the first dosage and removed approximately 24 h later, minutes before the next dosage. Absorbent pads were stored at -20 degrees C in plastic tubes until analysis. The target drugs were extracted in 5 mL of acetonitrile in the presence of 100 ng each of heroin-d9, 6-acetylmorphine-d3, and morphine-d3. After agitation for 30 min, the acetonitrile solution was divided into two portions: 2 mL for heroin testing and the remainder for testing for the other compounds. After evaporation, the residue of the first portion was reconstituted in 35 microL of acetonitrile; the second was derivatized by silylation with 40 microL of N,O-bis(trimethylsilyl)trifluoroacetamide containing 10 mL/L trimethylchlorosilane. Drugs were analyzed by GC-MS in electron impact mode. Concentrations (nanograms per patch) ranged from 2.1 to 96.3 for heroin, 0 to 24.6 for 6-acetylmorphine, and 0 to 11.2 morphine. Except in one case, heroin was the major drug present in sweat, followed by 6-acetylmorphine and morphine. We observed no correlation between the doses of heroin administered and the concentrations of heroin measured in sweat.

R. Fogerson, D. Schoendorfer, J. Fay and V. Spiehler (1997). “Qualitative detection of opiates in sweat by EIA and GC-MS.[comment].” Journal of Analytical Toxicology 21(6): 451-8.

            Sweat was collected with the PharmChek sweat patch, and drugs were eluted from the collection pad of the patch. A solid-phase enzyme immunoassay (EIA) using microtiter plates was modified for the analysis of opiates in sweat. After opiate administration, sweat contains primarily parent opiate (heroin, codeine) and lipophilic metabolites (6-monoacetylmorphine [6-MAM]). The immunoassay was determined to have a cross-reactivity with codeine of 588%, with hydrocodone of 143%, with diacetylmorphine of 28%, and with 6-MAM of 30% relative to 100% for the morphine calibrators. The optimum cutoff concentration for this modified assay was determined by receiver operator characteristic analysis using 215 patches from 95 subjects to be 10 ng/mL morphine equivalents. At this cutoff concentration the assay had a diagnostic sensitivity of 86.9% and a diagnostic specificity of 92.8% versus gas chromatography-mass spectrometry (GC-MS), which was the reference method. The positive predictive value at a prevalence of 50% was 86%. The intra-assay precision at 10 ng/mL was 7.8%, and the interassay coefficient of variation (CV) was 39%. Analysis of spiked patches around the cutoff gave a percent positive threshold of approximately 50% between 10 and 15 ng/mL and a 95% confidence level for a positive result by the EIA between 20 and 25 ng/mL. Eighteen possible adulterants that could be injected into or under the patch were studied. Two (tile cleaner and detergent) can cause false-positive responses in the immunoassay. Two adulterants reduced response to spiked drug (Visine eye drops and Ben Gay ointment), which could cause a false-negative response. All results were confirmed by GC-MS. The clinical sensitivity and specificity for detecting drug use by analyzing sweat collected from human subjects following known doses of codeine (0, 30, and 60 mg orally) or heroin (20 mg intravenously) were 76 and 100%, respectively.

P. Kintz, C. Sengler, V. Cirimele and P. Mangin (1997). “Evidence of crack use by anhydroecgonine methylester identification.” Human & Experimental Toxicology 16(2): 123-7.

            A method using gas chromatography coupled to mass spectrometry for the determination of cocaine (COC) pyrolysis product, anhydroecgonine methylester (AEME), in plasma, saliva, urine, sweat and hair is described. The same procedure allows the simultaneous determination of COC, benzoylecgonine (BZE), ecgonine methylester (EME) and cocaethylene (CE). After suitable sample preparation (desorption of the sweat patch, acid hydrolysis of the hair) the target drugs were extracted using a 3-steps liquid-liquid extraction (pH 8.4) in presence of deuterated internal standards in chloroform-isopropanol-n-heptane (50 : 17 : 33, v/v). Derivatization was achieved using BSTFA+1% TMCS. Ions for AEME monitoring were m/z 82, 166, 152 and 181. Artifact formation from COC or EME of AEME during the injection was less than 0.5%. AEME was never detected in blood sample although the corresponding urine tested positive. Urine concentrations, in about 90 positive AEME samples, were in the range 5 to 1477 ng/ml. In one case of crack overdose, AEME in sweat was 53 ng/patch with a COC concentration of 1231 ng/patch. AEME in saliva ranged from 5 to 18 ng/ml in the same case. Finally, AEME was identified in 32 hair specimens of crack abusers including fetal hair, with concentrations in the range 0.20 to 21.56 ng/mg. These results suggest that AEME can be a useful marker for the detection of COC smoking in clinical and forensic cases.

D. A. Kidwell, M. A. Blanco and F. P. Smith (1997). “Cocaine detection in a university population by hair analysis and skin swab testing.” Forensic Science International 84(1-3): 75-86.

            The ability to detect cocaine use/exposure by either hair or sweat analysis was compared in a random population of adults at a major US university. Sweat was obtained by wiping the forehead with a cosmetic puff containing isopropanol. Using cut-off levels for sweat of 2.2 ng cocaine/wipe and of hair of 0.05 ng cocaine/mg hair, sweat detected two times more cocaine use/exposure than did hair. Sweat analysis detected a use rate of 12% compared to a 6% rate by hair analysis, both greater than the 2% that would be expected in this population. The high rate of detection was surprising and suggests that use of, if not exposure to, cocaine is underreported. Controlled experiments showed that cocaine could remain on the skin for about 3 days after external exposure. At the current state of knowledge, sweat appears to measure both use and exposure. Nevertheless, sweat testing could be used in several scenarios (such as roadside driving while intoxicated) where the case of collection and testing of sweat could outweigh the passive exposure considerations. Cocaine concentrations in skin swabs > 15 ng/swab would appear to indicate recent use/exposure.

G. Skopp, L. Potsch and M. R. Moeller (1997). “On cosmetically treated hair--aspects and pitfalls of interpretation.” Forensic Science International 84(1-3): 43-52.

            Popular hair cosmetic treatments like bleaching or permanent waving were found to affect the stability of incorporated drugs and to cause alterations of the fibers at an ultrastructural level. This may result in a partial or complete loss of drug substances, depending on the particular drug molecule and on its concentration prior to the cosmetic treatment. Moreover, from literature, there is some evidence that drug molecules are not only incorporated into the growing fiber by passive diffusion from blood into the matrix cells and melanocytes, but that the substances enter the hair also via perspiration such as sweat and sebum. Since permed and bleached hair shows an enhanced sorption capacity, the risk of false positives or an unusually high drug concentration in cosmetically treated hair was under investigation. Virgin, permed, mildly as well as severely bleached tresses were exposed to artificial sweat or sebum containing cocaine, benzoylecgonine, 6-acetylmorphine, morphine and codeine (500 ng/g). Except codeine, the concentrations measured by GC/MS were very small and quite close to the detection limit indicating a minor importance of drug uptake into hair fiber from the endogenous-exogenous shunt via sebum or sweat. From the results it is concluded that an increased risk of false positive results in hair analysis on bleached and permanent waved hair fibers does exist, but is not particularly severe. 

V. Spiehler, J. Fay, R. Fogerson, D. Schoendorfer and R. S. Niedbala (1996). “Enzyme immunoassay validation for qualitative detection of cocaine in sweat.” Clinical Chemistry 42(1): 34-8.

            A solid-phase enzyme immunoassay (EIA) involving microtiter plates was modified for analysis of cocaine in sweat. Sweat was collected with the PharmChek sweat patch and drugs were eluted from the collection pad of the patch. The sweat contained primarily parent cocaine. The assay was determined to have cross-reactivity for cocaine of 102% relative to 100% for the benzoylecgonine (BE) calibrators and for cocaethylene of 148%. The optimum cutoff concentration for this modified assay, determined by receiver-operating characteristic curve analysis, was 10 micrograms/L cocaine or BE equivalents. At this concentration the assay had 94.5% sensitivity and 99.1% specificity vs gas chromatography-mass spectrometry (GC-MS) as an acceptable indicator of the true clinical state. The positive predictive value at a prevalence of 50% was 99%. Threshold analysis for positives suggested that the 95% confidence interval for a positive result by the EIA was between 12.5 and 15 micrograms/L and that quality-control samples at 5 and 15 micrograms/L could be run with each batch to certify the precision around the cutoff. All positive samples must be confirmed by GC-MS. The sensitivity and specificity of the overall analysis system (immunoassay screen and GC-MS confirmation) was 86% and 97%, with known cocaine dosing of volunteers as the acceptable indicator of the true clinical state.

P. Kintz (1996). “Drug testing in addicts: a comparison between urine, sweat, and hair.” Therapeutic Drug Monitoring 18(4): 450-5.

            The standard in drug testing is the immunoassay screen, followed by a gas chromatography/mass spectrometry confirmation conducted on a urine sample. Recently sweat and hair analyses were proposed for identifying drug abusers. Specimens can be collected under close supervision without embarrassment and are not subject to evasive maneuvers. In contrast with urine, hair analysis has a wide window of detection, ranging from months to years, and provides information concerning the severity and pattern of an individual's drug abuse. Testing individuals for illicit drugs with sweat patches worn continually would provide effective coverage for a week. Studies conducted in a detoxification center have shown that hair analysis is more sensitive for detecting illicit drug use than is urine screening. My experience in drug testing is discussed in the light of the existing literature.

S. Balabanova, E. Schneider, R. Wepler, B. Hermann, H. J. Boschek and H. Scheitler (1992). “[Significance of drug determination in pilocarpine sweat for detection of past drug abuse].” Beitrage zur Gerichtlichen Medizin. 50: 111-5.

            The presence of cocaine, morphine and methadone in sweat samples obtained after stimulation of the eccrine sweat glands, from drugs users after six drugs-free days, was investigated. The stimulation of the sweat elimination was proved using pilocarpine-iontophoresis every hour for 7 hours. The drugs concentrations were determined by radioimmunoassay. Consequently, the values measured represent the sum of the drug and its metabolites. Measurable levels of cocaine, morphine and methadone were obtained after the third stimulation of the glands.