Confirmation of LSD intoxication by analysis of serum and urine

Serum and urine specimens of 31 patients with suspected lysergic acid diethylamide (LSD) intoxication were analyzed for LSD by both radioimmunoassay (RIA) and high-pressure liquid chromatography (HPLC). The RIA assay, using 0.1 ng/mL as the limit of detection instead of the manufacturer's recommendation of 0.5 ng/mL, was positive for LSD in 13 blood and urine specimens from 14 patients. Results were compared to HPLC analysis using methysergide instead of lysergol as the internal standard and a limit of detection of 0.5 ng/mL. HPLC detected LSD in 9 of 13 serum specimens and 11 of 13 urine specimens that had tested positive by RIA. Of 18 patients with a final clinical diagnosis of LSD intoxication, LSD was detected by RIA in 14 patients and by HPLC in 11 patients. For 13 other cases in which the final diagnosis was a condition other than LSD intoxication, serum and urine assays for LSD were negative in all cases by both techniques. LSD assays have not been generally available in clinical laboratories. We conclude that the qualitative determination of LSD in either serum or urine by a commercially available radioimmunoassay has made it possible to provide reliable laboratory confirmation of LSD intoxication.     

Bupropion interference with immunoassays for amphetamines and LSD

A 50-year-old male patient suddenly had lost consciousness, although he had previously been healthy. On arrival at hospital seizures arose. The authors investigated a urine sample of the patient, and performed toxicological drug screening with immunochemical Cloned Enzyme Donor Immunoassay (CEDIA) assays. Positive findings for amphetamines and LSD could not be confirmed. Using gas chromatography/mass spectrometry (GC/MS), and liquid chromatography/mass spectrometry (LC/MS), the authors identified bupropion, a drug used to aid in smoking cessation, as the interfering compound, which may cause false-positive results for amphetamines and LSD using the CEDIA assays.     

Rapid detection of benzoylecgonine in vitreous humor by enzyme immunoassay

The usual specimens submitted by a medical examiner for toxicological analysis include blood, urine, bile, vitreous humor, stomach contents, and solid-organ tissue. The detection of drugs in these specimens typically involves a combination of techniques including colorimetry, immunoassay, and gas chromatography. Although many laboratories rely principally on urine for the detection of drugs of abuse by immunoassay, these assays may be applied to other specimen types. An evaluation of Microgenics Corporation's cloned enzyme donor immunoassay (CEDIA) was conducted in order to evaluate its use in the detection of cocaine/cocaine metabolites in vitreous humor specimens. During a 14-month period, 392 vitreous humor specimens were analyzed by the CEDIA DAU Cocaine assay. Instrument parameters were set according to published manufacturer's guidelines. All presumptive positive immunoassay results prompted confirmatory testing and quantitation by gas chromatography-mass spectrometry (GC-MS) of other specimens including blood. Vitreous humor specimens were not tested by GC-MS. Using a approximately 100-ng/mL cutoff, the CEDIA assay produced 23 presumptive positive results, 22 of which were confirmed by GC-MS. The only specimen which could not be confirmed, elicited an immunoassay screen value near the cutoff limit. Routine analysis of blood, urine, bile, and/or bladder wash specimens by gas chromatography-nitrogen phosphorus detection revealed the presence of cocaine/cocaine metabolites in only 7 (31.8%) of the 22 confirmed cases. The concentration ranges of cocaine and benzoylecgonine in the blood specimens were none detected to 337 ng/mL and 17 to 8598 ng/mL, respectively. Cocaethylene was not detected in these cases. Analysis of vitreous humor specimens by CEDIA improved the detection rate of cocaine/cocaine metabolites by 0.7% in the cases submitted to our laboratory during the 14-month period.     

Development and evaluation of an improved method for screening of amphetamines.

We developed a homogeneous immunoassay method to eliminate false-positive amphetamine results caused by cross-reactive substances, including over-the-counter allergy and cold medications. This method uses a neutralizing antibody that binds to amphetamines but does not bind to the labeled amphetamine conjugate used in the assay. The amount of neutralizing antibody is sufficient to reduce the assay signal resulting from authentic amphetamine and methamphetamine, but not the signal resulting from cross-reactants. This concept was implemented using the CEDIA DAU Amphetamines assay on Hitachi 747 and 717 clinical chemistry analyzers. Urine samples were tested using the standard, unmodified reagents in one channel and reagents containing the neutralizing antibody in a second channel. The difference in rate between the two tests was calculated by the analyzer; true-positive samples showed a significantly greater decrease in assay signal in response to neutralizing antibody as compared with false-positive samples. The neutralization method was evaluated in two studies using 448 samples that tested positive in the initial CEDIA DAU Amphetamines screening test. The samples were separated into categories of 154 true-positive samples and 294 false-positive samples based upon a secondary screen with the Abbott FPIA Amphetamines assay followed by gas chromatography-mass spectrometry (GC-MS) testing using the HHS (SAMHSA) cutoff criteria. The CEDIA neutralization test successfully identified all 154 of the GC-MS confirmed positive samples. The test successfully identified as false positive 251 out of the 294 (85.4%) samples that failed to confirm by GC-MS.     

Detection of opiate use in a methadone maintenance treatment population with the CEDIA 6-acetylmorphine and CEDIA DAU opiate assays

Heroin, with a plasma half-life of approximately 5 min, is rapidly metabolized to 6-acetylmorphine (6-AM). 6-AM, a specific marker for heroin use, which also has a short half-life of only 0.6 h, is detected in urine for only a few hours after heroin exposure. Ingestion of poppy seeds and/or licit opiate analgesics can produce positive urine opiate tests. This has complicated the interpretation of positive opiate results and contributed to the decision to raise opiate cutoff concentrations and to require 6-AM confirmation in federally mandated workplace drug-testing programs. Microgenics Corp. has developed the CEDIA 6-AM assay, a homogeneous enzyme immunoassay for semiquantitative determination of 6-AM in human urine, in addition to its CEDIA DAU opiate assay. Urine specimens were collected 3 times per week from 27 participants enrolled in a clinical research trial evaluating a contingency management treatment program for heroin and cocaine abuse. Of the 1377 urine specimens screened, 261 (18.9%) were positive for opiates at > or = 300 ng/mL, 153 (11.1%) were positive for opiates at > or = 2000 ng/mL, and 55 (4.0%) were positive for 6-AM at > or = 10 ng/mL. For opiate-positive screens > or = 300 and > or = 2000 ng/mL, 91.3% and 80.8% confirmed positive for morphine or codeine at the respective gas chromatography-mass spectrometry (GC-MS) cutoffs. All specimens screening positive for 6-AM also confirmed positive by GC-MS at > or = 10 ng/mL. Increasing the opiate screening and confirmation cutoffs for the federal workplace drug-testing program resulted in 8% fewer opiate-positive tests; however, recent heroin use was not affected by this change.     

Quantitative determination of LSD and a major metabolite, 2-oxo-3-hydroxy-LSD, in human urine by solid-phase extraction and gas chromatography-tandem mass spectrometry.

An assay has been developed for quantitative determination of lysergic acid diethylamide (LSD) and a major metabolite of LSD in human urine at concentrations as low as 10 pg/mL. In most LSD-positive urine samples the metabolite, 2-oxo-3-hydroxy-LSD, is present at higher concentrations than LSD and can be detected for a longer time than LSD after ingestion of the drug. Urine samples are extracted using Varian Bond Elut Certify extraction cartridges. Confirmatory identification is accomplished by trimethylsilylation of LSD and 2-oxo-3-hydroxy-LSD, followed by gas chromatography-tandem mass spectrometry analysis using positive ion chemical ionization and selected reaction monitoring. Commercially available lysergic acid methylpropylamide and 2-oxo-3-hydroxy-LAMPA are used as internal standards. With selected reaction monitoring, both compounds gave linear calibration curves from 10 pg/mL to 5000 pg/mL. Forty-nine human urine samples that had previously been shown to contain LSD were reanalyzed by the new method. These samples showed an average LSD concentration of 357 pg/mL and an average 2-oxo-3-hydroxy-LSD concentration of 3470 pg/mL. Additional experiments using clinical samples in which two subjects were dosed with LSD support the conclusion that analysis for 2-oxo-3-hydroxy-LSD can permit identification of LSD users for a longer period following ingestion than analysis for the parent drug.     

Performance characteristics of selected immunoassays for preliminary test of 3,4-methylenedioxymethamphetamine, methamphetamine, and related drugs in urine specimens

Eight commercially available immunoassays for amphetamines (DRI Amphetamines, CEDIA DAU Amphetamines-Semiquantitative, EMIT d.a.u. Monoclonal Amphetamine/Methamphetamine, Synchron CX Systems AMPH, TDx/TDxFLx Amphetamine/Methamphetamine II, CEDIA Amphetamines/Ecstasy, COBAS INTEGRA Amphetamines, and Abuscreen((R)) OnLine HS Amphetamine/MDMA) are evaluated for their effectiveness in serving as the preliminary test methodology for the analysis of 3,4-methylenedioxymethamphetamine/3,4-methylenedioxyamphetamine (MDMA/MDA) and methamphetamine/amphetamine (MA/AM). Standard solutions (in urine matrix) of MDMA, MDA, MA, and AM are used to determine these immunoassays' reactivities (or cross-reactivities) toward these compounds of interest. Case specimens containing MDMA/MDA and MA/AM are also used to study the correlations of the apparent immunoassay MDMA (or MA) concentrations and the gas chromatographic-mass spectrometric concentrations of these compounds. Data resulting from this study suggest that CEDIA Amphetamines/Ecstasy can best predict the concentrations of MDMA and MA in case specimens and can also detect the presence of MDMA at low levels, whereas Abuscreen OnLine HS Amphetamine/MDMA can detect both MDMA and MA at low concentrations.     

Evaluation of four immunoassay screening kits for the detection of benzodiazepines in urine

The identification of benzodiazepines (BZD) in biological fluids can be a challenging process. The large number of various BZD in pharmaceutical distribution, with similar core structures, and individual metabolic profiles all contribute to a complicated and time-consuming analysis. The purpose of the current study was to evaluate the performance of four commercially available immunoassay urine screening kits for use in a forensic urine analysis testing program. The four kits included the Roche Benzodiazepine Plus KIMS assay, Microgenics CEDIA Benzodiazepine assay, Microgenics CEDIA high sensitivity assay with beta-glucuronidase, and Microgenics DRI reagent ready Benzodiazepine assay. Each kit was evaluated for linearity, precision, accuracy, carryover, reagent specificity, and confirmation rates. BZD reagent specificity was compared by analysis of 55 structurally dissimilar compounds to BZD. Negative responses to all 55 compounds were elicited by all four reagent assays. Cross-reactivity for the assays was demonstrated by detecting 27 structurally similar BZD. In addition, greater than 10,000 randomly collected urine samples were screened at a 200 ng/mL cutoff for each assay. Positive samples were confirmed by gas chromatography-mass spectrometry using a panel of 13 BZD confirmation standards. The Microgenics CEDIA high sensitivity assay demonstrated the highest positive screening rate as well as the highest confirmation rate of the four assays.     

The development and application of a gas chromatography-mass spectrometric (GC-MS) assay to determine the presence of 2-oxo-3-hydroxy-LSD in urine

An accurate and reproducible gas chromatography-mass spectrometry (GC-MS) analytical method was developed to enable the Laboratory to determine the presence and concentration of the 2-oxo-3-hydroxy metabolite of lysergic acid diethylamide (OH-LSD) in urine. The limit of detection was 0.5 ng/mL, with a limit of quantitation established as 1.0 ng/mL. The assay was reproducible and linear over the concentration range 0.5-50.0 ng/mL, with a typical correlation coefficient (r2) of 0.997. This method was subsequently applied to the analysis of specimens submitted for routine drugs of abuse screening as part of an audit into the prevalence of LSD abuse in the West Midlands, U.K. This initial pilot study was performed using urine specimens obtained from 600 suspected LSD abusers. Following immunoassay screening, only 25 (6 female and 19 male subjects) were found to be LSD positive, but only 11 were confirmed as containing OH-LSD by GC-MS. The concentrations determined in these specimens ranged from 1.7 to 55.8 ng/mL (mean 11.0, median 5.4). This rapid and sensitive technique should enable the Laboratory to perform future audits of LSD abuse throughout the West Midlands and facilitate differential diagnoses to be made between drug misuse and underlying organic disorders.     

Comparison of the Microgenics CEDIA heroin metabolite (6-AM) and the Roche Abuscreen ONLINE opiate immunoassays for the detection of heroin use in forensic urine samples

Current Department of Defense (DoD) and Department of Health and Human Services (HHS) procedures for the detection of heroin abuse by testing urine utilize an initial opiate (codeine/morphine) immunoassay (IA) screen followed by gas chromatography-mass spectrometry (GC-MS) confirmation of 6-acetylmorphine (6-AM), if the morphine concentration is above established cutoff. An alternative to the current opiates screen for heroin abuse is the direct IA for the metabolite of heroin, 6-acetylmorphine. In this regard, the performance of the Microgenics CEDIA heroin metabolite (6-AM) screening reagent was assessed. This evaluation was conducted on the P module of a Hitachi Modular automated IA analyzer calibrated using 6-AM at 10 ng/mL. Reproducibility, linearity, accuracy, sensitivity, and interferences associated with use of the 6-AM IA reagent were evaluated. The IA reagent precision (percent coefficient of variation (%CV)) around each of seven standards was less than 0.63%, with a linearity (r(2)) value of 0.9951. A total of 37,713 active duty service members' urine samples were analyzed simultaneously using the CEDIA heroin metabolite (6-AM) reagent and the Roche Abuscreen ONLINE opiate reagent to evaluate both the prevalence rate of 6-AM in the demographic group and the sensitivity and specificity of the reagents for the detection of heroin use. Of the 37,713 samples tested using the CEDIA heroin metabolite (6-AM) reagent, three samples screened positive at the DoD and HHS cutoff of 10 ng/mL. One of the three samples confirmed positive for 6-AM by GC-MS above the cutoff of 10 ng/mL, the two remaining samples confirmed negative for 6-AM at a GC-MS limit of detection (LOD) of 2.1 ng/mL. In contrast, the Roche Abuscreen ONLINE opiate IA produced 74 opiate-positive results for codeine/morphine, with 6 of the 74 specimens confirming positive for morphine above the DoD cutoff concentration of 4000 ng/mL (8% DoD morphine confirmation rate), only one of the 74 opiate-positive screen specimens confirmed positive for 6-AM above the 10 ng/mL GC-MS cutoff concentration. As a further check of the sensitivity and specificity of the Microgenics 6-AM IA reagent, human urine samples (n = 87) known to contain 6-AM by GC-MS, were re-analyzed using both IA reagents. All 87 of the samples screened positive using the CEDIA heroin metabolite (6-AM) assay. However, using the Roche ONLINE opiate reagent, 12 of the known 6-AM positives screened negative at the DoD and HHS screening cutoff of 2000 ng/mL (morphine). Of the remaining 75 samples that screened positive by the ONLINE opiate reagent, five of the samples did not contain morphine above the DoD GC-MS cutoff concentration of 4000 ng/mL and would not have required 6-AM analysis. However, under the HHS GC-MS morphine cutoff concentration of 2000 ng/mL all 75 samples would have required 6-AM analysis. Furthermore, using the current DoD opiate screen, 17 out of 87 samples known to contain 6-AM would have gone undetected (19.5% false-negative rate); additionally, even under the more stringent HHS opiate screening standards 12 out of the 87 samples known to contain 6-AM would also have gone undetected (13.8% false-negative rate). The Microgenics CEDIA heroin metabolite (6-AM) reagent assay appears well adapted for the rapid and specific detection of heroin abuse as an alternative for, or an adjunct test to, the current opiates (codeine/morphine) IA screening procedure.     

Direct semiquantitative screening of drugs of abuse in serum and whole blood by means of CEDIA DAU urine immunoassays.

The purpose of this study was to test the direct applicability of CEDIA DAU urine immunoassays to serum or whole blood. The performance of the urine assays for sensitive screening of amphetamines (AMP), benzoylecgonine (BZE), benzodiazepines (BENZ), methadone (MET), opiates (OPI), and tetrahydrocannabinol carboxylic acid (THCCOOH) was evaluated on the BM/Hitachi 911 analyzer with unpretreated serum and whole blood. The limit of detection was 0 ng/mL for all tests. Cutoff values were set from 10 to 40 ng/mL for the different assays. The assays were found to be linear between the following concentrations: AMP 0-2500 ng/mL, BZE 0-1200 ng/mL, BENZ 0-1600 ng/mL, MET 0-600 ng/mL, OPI 0-720 ng/mL, and THCCOOH 24-60 ng/mL. Precision results (within run) for different concentrations were as follows: AMP 3.1-5.7%, BZE 2.4-6.6%, BENZ 4.3-8.0%, MET 2.0-5.5%, OPI 2.8-7.6%, and THCCOOH 1.4-2.4%. Between-run results were as follows: AMP 8.7-15.5%, BZE 6.4-7.5%, BENZ 8.2-15.8%, MET 2.7-5.1%, OPI 4.3-11.2%, and THCCOOH 2.6-7.4%. Sensitivity, specificity, and comparison of CEDIA semiquantitation with GC-MS quantitative results were performed on 500 original serum and whole blood samples. The data provided sufficient documentation to use the CEDIA urine-screening technique without any adaptation as a sensitive serum/whole blood screening for BZE, BENZ, MET, OPI, and THCCOOH. Serum screening for amphetamines is not sensitive enough in the unchanged urine mode. It will require some adaptation to a serum mode (probably a higher sample volume [BM/Hitachi 911] combined with protein precipitation of the sample).     

Evaluation of immunoassays for cannabinoids in urine

A comparison was made of several cannabinoid urine assays. Two hundred randomly selected urine specimens were initially screened by two enzyme immunoassays (EMIT-st and EMIT-d.a.u.) and a radioimmunoassay (Abuscreen RIA). Selected specimens found positive by any of these methods were further analyzed by gas-liquid chromatography with flame ionization detection (GLC/FID), gas chromatography/mass spectrometry (GC/MS), and an experimental RIA from Research Triangle Institute (RTI RIA). The GLC/FID method gave confirmations in 69 to 92% of the samples, depending on the method used and the cut-off employed. GC/MS confirmed 98% of the EMIT and RIA positives using a low cut-off (20 ng/mL). All RIA positives at 100 ng/mL were confirmed by GC/MS. There was complete agreement between the RTI RIA and the EMIT assays, but not with the Abuscreen RIA at the 100 ng/mL cut-off. The study illustrates that care must be exercised in establishing assay cut-offs and the designation of false positive results.     

Measurement of lysergic acid diethylamide (LSD) in human plasma by gas chromatography/negative ion chemical ionization mass spectrometry

A previously reported procedure for quantification of LSD in urine was modified to permit measurement of the drug in plasma. After addition of deuterium-labelled LSD, the plasma is extracted and the extract is treated with trifluoroacetylimidazole to convert the LSD to its N-trifluoroacetyl derivative. The derivatized LSD is analyzed by capillary column gas chromatography/negative ion chemical ionization. Plasma fortified with known concentrations of LSD gave linear responses from 0.1 to 3.0 ng/mL with this assay. The method was used to determine pharmacokinetic parameters for LSD after oral administration (1 microgram/kg) to a male volunteer. The apparent plasma half-life was determined to be 5.1 h. The peak plasma concentration of 1.9 ng/mL occurred 3 h after administration.     

A new highly specific buprenorphine immunoassay for monitoring buprenorphine compliance and abuse

Urine buprenorphine screening is utilized to assess buprenorphine compliance and to detect illicit use. Robust screening assays should be specific for buprenorphine without cross-reactivity with other opioids, which are frequently present in patients treated for opioid addiction and chronic pain. We evaluated the new Lin-Zhi urine buprenorphine enzyme immunoassay (EIA) as a potentially more specific alternative to the Microgenics cloned enzyme donor immunoassay (CEDIA) by using 149 urines originating from patients treated for chronic pain and opioid addiction. The EIA methodology offered specific detection of buprenorphine use (100%) (106/106) and provided superior overall agreement with liquid chromatography-tandem mass spectrometry, 95% (142/149) and 91% (135/149) using 5 ng/mL (EIA[5]) and 10 ng/mL (EIA[10]) cutoffs, respectively, compared to CEDIA, 79% (117/149). CEDIA generated 27 false positives, most of which were observed in patients positive for other opioids, providing an overall specificity of 75% (79/106). CEDIA also demonstrated interference from structurally unrelated drugs, chloroquine and hydroxychloroquine. CEDIA and EIA[5] yielded similar sensitivities, both detecting 96% (22/23) of positive samples from patients prescribed buprenorphine, and 88% (38/43) and 81% (35/43), respectively, of all positive samples (illicit and prescribed users). The EIA methodology provides highly specific and sensitive detection of buprenorphine use, without the potential for opioid cross-reactivity.     

Monitoring cyclosporine of pre-dose and post-dose samples using nonextraction homogeneous immunoassay

A nonextraction homogeneous immunoassay (CEDIA Cyclosporine Plus Assay) has been developed for the measurement of cyclosporine in predose (trough) and post-dose (C2 to C8) whole-blood samples. The method includes a low-range assay that measures cyclosporine from 25 to 450 ng/mL in pre-dose samples and a high-range assay that detects cyclosporine from 450 to 2000 ng/mL in post-dose samples. The high-range assay allows a direct measurement of post-dose samples without a dilution step. Alternatively, post-dose samples can be correctly measured by the low-range assay following a twofold dilution. Using an NCCLS precision protocol, the assay exhibited less than 10% CV or error less than the functional sensitivity. Functional sensitivity of the low-range assay was demonstrated at 20 ng/mL cyclosporine. Cross-reactivity was measured in the presence of cyclosporine and was found to be 4.4%, 19.8%, 16.4%, 0.9%, 1.0%, and 1.6% for metabolites AM1, AM9, AM4n, AM19, AM4n9, and AM1c, respectively. When 53 samples were evaluated using an HPLC method, the three most significant cross-reactive metabolites, AM1, AM4n, and AM9, exhibited an average concentration profile of 123%, 19%, and 0.06% of the parent cyclosporine, respectively. The average total contribution to cyclosporine quantification from these metabolites was estimated at 7.2% based on the percentage cross-reactivity of each metabolite in the CEDIA assay and the concentration of each metabolite as determined by HPLC. The method comparison study revealed a linear regression correlation of CEDIA = 1.095 x HPLC + 6.6, r = 0.972, for the low-range assay, and CEDIA = 1.018 x HPLC - 36.4, r = 0.968, for the high-range assay. In conclusion, the CEDIA Cyclosporine Plus Assay is a precise and accurate method for quantification of cyclosporine in pre-dose and post-dose samples.     

Evaluation of the immunotech cyclosporine direct radioimmunoassay for the determination of whole-blood cyclosporine in renal transplant patients

Therapeutic drug monitoring (TDM) of cyclosporine (CsA) has been an accepted as an essential tool in the management of solid organ transplant recipients. The authors evaluated a new CsA method, Immunotech cyclosporine direct radioimmunoassay (Beckman Coulter, Prague, Czech Republic), for the measurement of whole-blood CsA concentrations. The performance was compared with CEDIA Plus method as well as group mean data for HPLC and other immunoassays available from the International CsA Proficiency Testing Program (www.bioanalytics.co.uk). Regression analysis of patient samples gave a relationship of RIA = 1.0822 CEDIA(+) + 69.84 (r(2) = 0.933). External CsA-spiked proficiency-testing (PT) samples gave a regression equation of RIA = 0.9672 CEDIA(+) + 4.99 (r(2) = 0.996). The correlation with the CEDIA Plus method using patient specimens (hence, including CsA metabolites) suggested that the test RIA method possibly had slightly inferior specificity for parent CsA. The results suggest that the Immunotech cyclosporine direct RIA kit is suitable for the measurement of whole-blood CsA concentrations and maintained clinically acceptable analytic precision and accuracy, displaying CVs of less than 15% and biases of less than 10%. The PT program CsA-metabolite-free samples showed that calibration between methods was comparable with the possible exception of mFPIA/TDx.     

Application of the CEDIA 6-MAM assay to routine drugs-of-abuse screening

A total of 1010 urine specimens obtained from General Practitioners, drug dependency units, and hospitals throughout the West Midlands were screened using the Microgenics CEDIA 6-monoacetylmorphine (6-MAM) assay as a means of establishing its effectiveness as a screening technique to monitor heroin abuse. A total of 282 specimens screened positive for 6-MAM using the CEDIA 6-MAM assay. However, the presence of 6-MAM could not be confirmed by gas chromatography-mass spectrometry in 21 (7%) of the CEDIA-positive specimens. Morphine was identified in all of these specimens at free concentrations ranging between 410 microg/L to 2010 microg/L. The data presented from this preliminary investigation suggests that either there are substances present within the urine specimens, as yet undetermined, which are interfering with the assay or that there may be a greater degree of cross reactivity to other opiates than previously published. 6-MAM assays may be potentially useful rapid screening techniques for high-throughput drugs-of-abuse screening laboratories performing employment and pre-employment screening. However, all positive results will still need to be confirmed by a more sensitive and specific technique.     

Determination of LSD in urine by capillary column gas chromatography and electron impact mass spectrometry

A procedure for the determination of LSD (lysergic acid diethylamide) in urine at concentrations as low as 0.5 ng/ml is presented. After addition of deuterium-labeled LSD as the internal standard, a rapid n-butyl chloride extraction of LSD from urine at pH 8 is followed by formation of the trimethylsilyl (TMS) derivative by treatment with N,O-bis(trimethylsilyl)trifluoroacetamide. The TMS derivative of LSD is identified and quantified by selected ion monitoring with a fused-silica capillary column and electron impact ionization. The procedure was used to monitor LSD concentrations in urine for eight hours following oral administration of 70.5 micrograms of LSD to two human volunteers. Concentrations of LSD determined by the assay are compared with concentrations determined by two other methods of analysis, a radioimmunoassay and a high-performance liquid chromatographic (HPLC) assay. Data concerning the stability of LSD in urine are also presented.