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A gas chromatography mass spectrometry method to detect both the cocaine metabolite, benzoylecgonine, and a cocaine adulterant, levamisole
Abstracts
Fig. Mountain plot comparing LC–MS/MS to EIA and RIA 25-OH-D assays.
doi:10.1016/j.clinbiochem.2012.07.058
P558 A gas chromatography mass spectrometry method to detect both the cocaine metabolite, benzoylecgonine, and a cocaine adulterant, levamisole A. Rutledge, P. Hureau, J. Zeidler Hamilton Regional Laboratory Medicine Program, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada L8L 2X2 Objectives: Levamisole, an animal de-worming agent, is now added to cocaine in South America. Consequently, most cocaine in Canada contains levamisole. In some people, levamisole causes neutropenia or vasculitis. We wanted to modify our gas chromatography mass spectrometry (GC–MS) method for detection of the cocaine metabolite benzoylecgonine (BE) to also be able to detect levamisole. Methods: The BE method involved addition of deuterated BE internal standard to urine, solid-phase extraction with cation exchange columns, elution with ethyl acetate–methanol–triethylamine, evaporation of the elution reagent, and reconstitution with N,Obis(trimethylsilyl)trifluoroacetamide/trimethylchlorosilane (BSTFA/ TMCS) and toluene. Silylation of levamisole with BSTFA/TMCS was incompatible with detection by GC–MS, but was necessary to detect BE. Therefore, in order to detect BE and levamisole from the same extraction, we reconstituted the dried extracted urine with toluene first, ran the samples on the GC–MS with single ion monitoring (SIM) to detect levamisole (m/z 101, 148, 204), and added BSTFA/TMCS before running the samples with a SIM method for BE. Results: The limit of detection is a levamisole concentration in urine of approximately 40 ng/mL. Levamisole recoveries of at least 70% are achievable. During the first two months of 2012, out of 16 urine samples sent for confirmation of the presence of cocaine, 15 (94%) were positive for levamisole. Conclusions: By introducing a slight modification in our protocol, we can now detect levamisole and BE, with a minimum of extra work or expense. The presence of levamisole in urine, associated with cocaine use, may explain some cases of neutropenia or vasculitis. doi:10.1016/j.clinbiochem.2012.07.059
P559 Pharmacogenetics and chronic pain management J.L.V. Shawa, B.M. Kapura,b a Department of Laboratory Medicine and Pathobiology, University of Toronto, Canada
1117
b
Division of Clinical Pharmacology and Toxicology, Hospital for Sick Children, Toronto, ON, Canada Objectives: To review the literature surrounding the role for pharmacogenetic testing in the medical management of patients with chronic pain. Methods: A systemic literature search was performed using Pubmed with the keywords “Pharmacogenetics and Pain Management”. Relevant articles were reviewed as well as articles cited therein. Results: Current treatment strategies for chronic pain follow the World Health Organization (WHO) pain ladder and opioids remain the mainstay of medical treatment for chronic pain, both cancer and noncancer. Several genes have been shown to be associated with altered pharmacokinetics and pharmacodynamics of certain pain management drugs. The majority of studies of pharmacogenetic testing in pain management patients focus on one gene and its effect on drug metabolism in isolation. There is a paucity of evidence that pharmacogenetic testing in chronic pain patients results in better analgesia with less adverse drug effects. There are data to suggest that monitoring of serum drug and/or metabolite levels may lead to better patient outcomes. Conclusions: Pharmacogenetics only partially explains the altered drug metabolism between individuals. Furthermore, the metabolism of most drugs involves more than one enzyme and can therefore be affected by multiple genes. The metabolism of pain medications can also be affected by many other factors, such as drug–drug interactions, dosing, disease co-morbidity, nutritional status, gender and age. Measurement of serum drug and metabolite concentrations likely provides more individualized information about the drug metabolism in a patient, since serum concentrations account for all of the various factors affecting drug metabolism.
doi:10.1016/j.clinbiochem.2012.07.060
P560 Validity of calculating pediatric reference intervals using hospital patient data: A comparison of the modified Hoffman approach to CALIPER reference intervals obtained in healthy children J.L.V. Shawa,b, D. Konfortea,b, T. Binesh Marvastia,b, J.S. Hamidc, D.A. Colantonioa,b, K. Adelia,b a Department of Laboratory Medicine and Pathobiology, University of Toronto, Canada b Clinical Biochemistry Division, Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, ON, Canada c Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON, Canada Objectives: To compare pediatric reference intervals calculated using hospital-based patient data with those calculated using samples collected from healthy children in the community. Methods: Hospital-based data for 13 analytes (calcium, phosphate, iron, ALP, cholesterol, triglycerides, creatinine, direct bilirubin, total bilirubin, ALT, AST, albumin and magnesium) collected between 2007 and 2011 were obtained. The data for each analyte were partitioned by age and gender as previously defined by the CALIPER study. Outliers in each partition were removed using the Tukey method. The cumulative frequency of each measured value was calculated and plotted. Piece-wise regression determined the linear portion of the resulting graph using the statistical software R. Linear regression determined an equation for the linear portion in each partition and reference intervals were calculated by extrapolating to identify the 2.5th and 97.5th percentiles in each partition. Using the reference change value (RCV) as criteria, these calculated reference intervals were compared to those reported previously as part of the CALIPER study.
Fig. Mountain plot comparing LC–MS/MS to EIA and RIA 25-OH-D assays.
doi:10.1016/j.clinbiochem.2012.07.058
P558 A gas chromatography mass spectrometry method to detect both the cocaine metabolite, benzoylecgonine, and a cocaine adulterant, levamisole A. Rutledge, P. Hureau, J. Zeidler Hamilton Regional Laboratory Medicine Program, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada L8L 2X2 Objectives: Levamisole, an animal de-worming agent, is now added to cocaine in South America. Consequently, most cocaine in Canada contains levamisole. In some people, levamisole causes neutropenia or vasculitis. We wanted to modify our gas chromatography mass spectrometry (GC–MS) method for detection of the cocaine metabolite benzoylecgonine (BE) to also be able to detect levamisole. Methods: The BE method involved addition of deuterated BE internal standard to urine, solid-phase extraction with cation exchange columns, elution with ethyl acetate–methanol–triethylamine, evaporation of the elution reagent, and reconstitution with N,Obis(trimethylsilyl)trifluoroacetamide/trimethylchlorosilane (BSTFA/ TMCS) and toluene. Silylation of levamisole with BSTFA/TMCS was incompatible with detection by GC–MS, but was necessary to detect BE. Therefore, in order to detect BE and levamisole from the same extraction, we reconstituted the dried extracted urine with toluene first, ran the samples on the GC–MS with single ion monitoring (SIM) to detect levamisole (m/z 101, 148, 204), and added BSTFA/TMCS before running the samples with a SIM method for BE. Results: The limit of detection is a levamisole concentration in urine of approximately 40 ng/mL. Levamisole recoveries of at least 70% are achievable. During the first two months of 2012, out of 16 urine samples sent for confirmation of the presence of cocaine, 15 (94%) were positive for levamisole. Conclusions: By introducing a slight modification in our protocol, we can now detect levamisole and BE, with a minimum of extra work or expense. The presence of levamisole in urine, associated with cocaine use, may explain some cases of neutropenia or vasculitis. doi:10.1016/j.clinbiochem.2012.07.059
P559 Pharmacogenetics and chronic pain management J.L.V. Shawa, B.M. Kapura,b a Department of Laboratory Medicine and Pathobiology, University of Toronto, Canada
1117
b
Division of Clinical Pharmacology and Toxicology, Hospital for Sick Children, Toronto, ON, Canada Objectives: To review the literature surrounding the role for pharmacogenetic testing in the medical management of patients with chronic pain. Methods: A systemic literature search was performed using Pubmed with the keywords “Pharmacogenetics and Pain Management”. Relevant articles were reviewed as well as articles cited therein. Results: Current treatment strategies for chronic pain follow the World Health Organization (WHO) pain ladder and opioids remain the mainstay of medical treatment for chronic pain, both cancer and noncancer. Several genes have been shown to be associated with altered pharmacokinetics and pharmacodynamics of certain pain management drugs. The majority of studies of pharmacogenetic testing in pain management patients focus on one gene and its effect on drug metabolism in isolation. There is a paucity of evidence that pharmacogenetic testing in chronic pain patients results in better analgesia with less adverse drug effects. There are data to suggest that monitoring of serum drug and/or metabolite levels may lead to better patient outcomes. Conclusions: Pharmacogenetics only partially explains the altered drug metabolism between individuals. Furthermore, the metabolism of most drugs involves more than one enzyme and can therefore be affected by multiple genes. The metabolism of pain medications can also be affected by many other factors, such as drug–drug interactions, dosing, disease co-morbidity, nutritional status, gender and age. Measurement of serum drug and metabolite concentrations likely provides more individualized information about the drug metabolism in a patient, since serum concentrations account for all of the various factors affecting drug metabolism.
doi:10.1016/j.clinbiochem.2012.07.060
P560 Validity of calculating pediatric reference intervals using hospital patient data: A comparison of the modified Hoffman approach to CALIPER reference intervals obtained in healthy children J.L.V. Shawa,b, D. Konfortea,b, T. Binesh Marvastia,b, J.S. Hamidc, D.A. Colantonioa,b, K. Adelia,b a Department of Laboratory Medicine and Pathobiology, University of Toronto, Canada b Clinical Biochemistry Division, Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, ON, Canada c Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON, Canada Objectives: To compare pediatric reference intervals calculated using hospital-based patient data with those calculated using samples collected from healthy children in the community. Methods: Hospital-based data for 13 analytes (calcium, phosphate, iron, ALP, cholesterol, triglycerides, creatinine, direct bilirubin, total bilirubin, ALT, AST, albumin and magnesium) collected between 2007 and 2011 were obtained. The data for each analyte were partitioned by age and gender as previously defined by the CALIPER study. Outliers in each partition were removed using the Tukey method. The cumulative frequency of each measured value was calculated and plotted. Piece-wise regression determined the linear portion of the resulting graph using the statistical software R. Linear regression determined an equation for the linear portion in each partition and reference intervals were calculated by extrapolating to identify the 2.5th and 97.5th percentiles in each partition. Using the reference change value (RCV) as criteria, these calculated reference intervals were compared to those reported previously as part of the CALIPER study.