Niu W.,Chongqing University |
Knight E.,Agriculture and Agri Food Canada |
Knight E.,Gamma Dynacare Medical Laboratories |
Xia Q.,Southwest University |
McGarvey B.D.,Agriculture and Agri Food Canada
Journal of Chromatography A | Year: 2014
Since retention times of compounds in GC-MS chromatograms always vary slightly from chromatogram to chromatogram, it is necessary to align chromatograms before comparing them in metabolomics experiments. Several software programs have been developed to automate this process. Here we report a comparative evaluation of the performance of eight programs using prepared samples of mixtures of chemicals, and an extract of tomato vines spiked with three concentrations of a mixture of alkanes. The programs included in the comparison were SpectConnect, MetaboliteDetector 2.01a, MetAlign 041012, MZmine 2.0, TagFinder 04, XCMS Online 1.21.01, MeltDB and GAVIN. Samples were analyzed by GC-MS, chromatograms were aligned using the selected programs, and the resulting data matrices were preprocessed and submitted to principal components analysis. In the first trial, SpectConnect, MetAlign and MetaboliteDetector correctly identified ≥90% of the true positives. In the second trial, MetAlign and MetaboliteDetector correctly identified 87% and 81% of the true positives, respectively. In addition, in both trials >90% of the peaks identified by MetAlign and MetaboliteDetector were true positives. © 2014.
Darragh A.,LabSource |
Snyder M.L.,LabSource |
Ptolemy A.S.,Gamma Dynacare Medical Laboratories |
Melanson S.,Harvard University
Pain Physician | Year: 2014
Background: Patients treated for chronic pain may frequently undergo urine drug testing to monitor medication compliance and detect undisclosed prescribed or illicit drug use. Due to the increasing use and abuse of benzodiazepines, this class of medications is often included in drug screening panels. However, immunoassay-based methods lack the requisite sensitivity for detecting benzodiazepine use in this population primarily due to their poor cross-reactivity with several major urinary benzodiazepine metabolites. A High Sensitivity Cloned Enzyme Donor Immunoassay (HS-CEDIA), in which betaglucuronidase is added to the reagent, has been shown to perform better than traditional assays, but its performance in patients treated for chronic pain is not well characterized. Objectives: To determine the diagnostic accuracy of HS-CEDIA, as compared to the Cloned Enzyme Donor Immunoassay (CEDIA) and Kinetic Interaction of Microparticles in Solution (KIMS) screening immunoassays and liquid chromatography-tandem mass spectrometry (LC-MS/MS), for monitoring benzodiazepine use in patients treated for chronic pain. Study Design: A study of the diagnostic accuracy of urine benzodiazepine immunoassays. Setting: The study was conducted at an academic tertiary care hospital with a clinical laboratory that performs urine drug testing for monitoring medication compliance in pain management. Methods: A total of 299 urine specimens from patients treated for chronic pain were screened for the presence of benzodiazepines using the HS-CEDIA, CEDIA, and KIMS assays. The sensitivity and specificity of the screening assays were determined using the LC-MS/MS results as the reference method. Results: Of the 299 urine specimens tested, 141 (47%) confirmed positive for one or more of the benzodiazepines/metabolites by LC-MS/MS. All 3 screens were 100% specific with no false-positive results. The CEDIA and KIMS sensitivities were 55% (78/141) and 47% (66/141), respectively. Despite the relatively higher sensitivity of the HS-CEDIA screening assay (78%; 110/141), primarily due to increased detection of lorazepam, it still missed 22% (31/141) of benzodiazepine-positive urines. The KIMS, CEDIA, and HS-CEDIA assays yielded accuracies of 75%, 79%, and 90%, respectively, in comparison with LC-MS/MS. Limitations: This study was limited by its single-site location and the modest size of the urine samples utilized. Conclusions: While the HS-CEDIA provides higher sensitivity than the KIMS and CEDIA assays, it still missed an unacceptably high percentage of benzodiazepine-positive samples from patients treated for chronic pain. LC-MS/MS quantification with enzymatic sample pretreatment offers superior sensitivity and specificity for monitoring benzodiazepines in patients treated for chronic pain.
Bourner G.,Gamma Dynacare Medical Laboratories |
De la Salle B.,UK National External Quality Assessment Scheme for General Haematology |
George T.,University of New Mexico |
Tabe Y.,Juntendo University |
And 4 more authors.
International Journal of Laboratory Hematology | Year: 2014
One of the many challenges facing laboratories is the verification of their automated Complete Blood Count cell counters for the enumeration of body fluids. These analyzers offer improved accuracy, precision, and efficiency in performing the enumeration of cells compared with manual methods. A patterns of practice survey was distributed to laboratories that participate in proficiency testing in Ontario, Canada, the United States, the United Kingdom, and Japan to determine the number of laboratories that are testing body fluids on automated analyzers and the performance specifications that were performed. Based on the results of this questionnaire, an International Working Group for the Verification and Performance of Automated Cell Counters for Body Fluids was formed by the International Council for Standardization in Hematology (ICSH) to prepare a set of guidelines to help laboratories plan and execute the verification of their automated cell counters to provide accurate and reliable results for automated body fluid counts. These guidelines were discussed at the ICSH General Assemblies and reviewed by an international panel of experts to achieve further consensus. © 2014 John Wiley & Sons Ltd.
Kapala J.,Gamma Dynacare Medical Laboratories |
Biers K.,Gamma Dynacare Medical Laboratories |
Cox M.,Gamma Dynacare Medical Laboratories |
Kamionka M.,Gamma Dynacare Medical Laboratories |
And 6 more authors.
Journal of Clinical Microbiology | Year: 2011
Aptima Combo 2 (AC2) Neisseria gonorrhoeae testing of 81,405 patients who were tested by culture and 14,666 who were AC2 tested for Chlamydia trachomatis detected 142 extra infections and confirmed 106 culture-positive samples (the positivity rate increased from 0.13 in testing by culture to 0.26 in testing by AC2). Retrievable AC2 positive samples were confirmed (98.5%) by an alternate AGC test. Copyright © 2011, American Society for Microbiology. All Rights Reserved.
Boyd J.M.,University of Calgary |
Krause R.,University of Calgary |
Waite G.,Gamma Dynacare Medical Laboratories |
Hui W.,Gamma Dynacare Medical Laboratories |
And 3 more authors.
Clinica Chimica Acta | Year: 2015
Background: There is limited information about the effects of instituting CLSI Document C56A recommended workflows for the automated detection of hemolysis, lipemia and icterus (HIL) in different clinical laboratories and patient populations. We describe a process to develop and tailor automated reporting rules that are appropriate for the local laboratory population. Methods: Automated decision algorithms were generated and applied to 2 high volume labs serving community and hospital populations. Proposed rules were applied to the datasets offline to predict the outcomes, and then were further optimized prior to implementation. Results: Introduction of automated serum indices decreased HIL flagging compared to manual flagging. Hemolysis flagging was the greatest in all 3 patient populations, and was successfully reduced for LD, CK and AST by optimized rules that incorporated both the H-index result and the analyte result. Changes in flagging rates were also patient population specific, particularly for icterus which was a problem in hospitalized populations but not in the community. Overall, concordance between manual and automated flagging methods was very low in both laboratories. Conclusions: We demonstrate that flagging algorithms may not be universally transferable due to lab specific and population specific factors and demonstrate the benefits of local, a priori testing of algorithms prior to implementation. © 2015 Elsevier B.V.
Abdou Mohamed M.A.,University of Toronto |
Abdou Mohamed M.A.,Zagazig University |
Raeesi V.,University of Toronto |
Turner P.V.,University of Guelph |
And 3 more authors.
Biomaterials | Year: 2016
The increasing occurrence of antimicrobial resistance among bacteria is a global problem that requires the development of alternative techniques to eradicate these superbugs. Herein, we used a combination of thermosensitive biocompatible polymer and gold nanorods to specifically deliver, preserve and confine heat to the area of interest. Our data demonstrates that this technique can be used to kill both Gram positive and Gram negative antimicrobial resistant bacteria in vitro. Our approach significantly reduces the antimicrobial resistant bacteria load in experimentally infected wounds by 98% without harming the surrounding tissues. More importantly, this polymer-nanocomposite can be prepared easily and applied to the wounds, can generate heat using a hand-held laser device, is safe for the operator, and does not have any adverse effects on the wound tissue and healing process. © 2016 Elsevier Ltd.
Chernesky M.,McMaster University |
Jang D.,McMaster University |
Portillo E.,McMaster University |
Smieja M.,McMaster University |
And 6 more authors.
Journal of Clinical Microbiology | Year: 2012
Chlamydia trachomatis and Neisseria gonorrhoeae are common causes of sexually transmitted infections, and there is interest in screening SurePath liquid-based Pap (L-Pap) samples with Aptima Combo 2 (AC2), Amplicor (AMP), and ProbeTec ET (PT) assays. SurePath L-Pap samples and a cervical swab (CS) were collected from 394 women attending health clinics in Hamilton and Toronto, ON, Canada. L-Pap samples were tested with the three assays prior to being processed for cytology, and the CS sample was tested with AC2. The prevalence of C. trachomatis was 8.9%, and that of N. gonorrhoeae was 1.5%. By using the positives from CS testing, as well as CS negatives corresponding to L-Pap samples that tested positive in 2 of 3 assays, the sensitivities of AC2, AMP, and PT for C. trachomatis in precytology samples were calculated to be 97.1% (34 of 35 positive samples were detected), 91.4% (32 of 35 were detected), and 77.1% (27 of 35 were detected), respectively. Six women were infected with N. gonorrhoeae. After cytology processing, the results of testing the remaining liquid in the L-Pap vial and the cell-enriched fraction for C. trachomatis by AC2 showed positive agreements of 98.9% (kappa [k], 0.93) and 98.7% (k, 0.92), respectively, with the results of testing precytology L-Pap samples. Although all testing showed high specificity, testing for C. trachomatis by AC2 was significantly more sensitive than testing by PT for SurePath samples (P = 0.02). Newer versions of AMP (Cobas 4800) and PT (Qx with XTR technology) need published evaluations for detecting C. trachomatis and N. gonorrhoeae in L-Pap samples. C. trachomatis testing can be performed with similar results on pre- and postcytology SurePath samples. Copyright © 2012, American Society for Microbiology. All Rights Reserved.
Bailey D.,Hospital for Sick Children |
Bailey D.,University of Toronto |
Bailey D.,Gamma Dynacare Medical Laboratories |
Bevilacqua V.,Hospital for Sick Children |
And 10 more authors.
Clinical Chemistry | Year: 2014
BACKGROUND: Studies of biological variation provide insight into the physiological changes that occur within and between study participants. Values obtained from such investigations are important for patient monitoring and for establishing quality specifications. In this study we evaluated the short-term biological variation of 38 chemistry, lipid, enzyme, and protein analytes in a pediatric population, assessed the effect of age partitions on interindividual variation, and compared the findings to adult values. METHODS: Four plasma samples each were obtained within 8 h from 29 healthy children (45% males), age 4-18 years. Samples were stored at -80 °C and analyzed in 3 batches, with samples from 9-10 study participants per batch. Within-person and between-person biological variation values were established using nested ANOVA after exclusion of outliers by use of the Tukey outlier test. Analytical quality specifications were established with the Fraser method. RESULTS: Biological variation coefficients and analytical goals were established for 38 analytes. Age partitioning was required for 6 analytes. Biological variation characteristics of 14 assays (37%) were distinct from adult values found in the Westgard database on biological variation. Biological variation characteristics were established for 2 previously unreported analytes, unconjugated bilirubin and soluble transferrin receptor. CONCLUSIONS: This study is the first to examine biological variation and to establish analytical quality specifications on the basis of biological variation for common assays in a pediatric population. These results provide insight into pediatric physiology, are of use for reference change value calculations, clarify the appropriateness of reference interval use, and aid in the development of quality management strategies specific to pediatric laboratories. © 2013 American Association for Clinical Chemistry.
Bailey D.,Hospital for Sick Children |
Bailey D.,University of Toronto |
Bailey D.,Gamma Dynacare Medical Laboratories |
Perumal N.,University of Toronto |
And 7 more authors.
Clinical Biochemistry | Year: 2014
Background: Poor vitamin D status (i.e. low serum 25-hydroxyvitamin D (25(OH)D)) has been associated with adverse clinical outcomes during pregnancy and childhood. However, the interpretation of serum 25(OH)D levels may be complicated by the presence of the C3-epimer of 25(OH)D. We aimed to quantify C3-epi-25(OH)D3 in pregnant women and fetuses, to explore the relationship of the C3-epimer between maternal and cord samples, and to establish whether infant C3-epimer abundance is explained by prenatal formation. Methods: In a sub-study of a randomized trial of prenatal vitamin D3, 25(OH)D3 and C3-epi-25(OH)D3 were quantified by LC-MS/MS in 71 sets of mother-fetus-infant serum samples, including maternal delivery specimens, cord blood, and infant specimens acquired at 3-28weeks of age. Results: Without supplementation, median concentrations of C3-epi-25(OH)D3 were higher in infants (6.80nmol/L) than mothers (0.45nmol/L) and cord blood (0nmol/L). However, there was substantial variation such that C3-epi-25(OH)D3 accounted for up to 11% (maternal), 14% (cord), and 25% (infant) of the total 25(OH)D3. Supplemental vitamin D3 significantly increased maternal-fetal C3-epi-25(OH)D3, and was a preferential source of C3-epi-25(OH)D3 compared to basal vitamin D, possibly due to C3-epi-cholecalciferol in the supplement. Multivariate regression did not suggest transplacental transfer of C3-epi-25(OH)D3, but rather indicated its generation within the fetal-placental unit from maternally-derived 25(OH)D3. Neither maternal nor fetal C3-epi-25(OH)D3 is accounted for the relatively high concentrations of infant C3-epi-25(OH)D3, suggesting rapid postnatal generation. Conclusions: C3-epi-25(OH)D3 is present in some pregnant women and fetuses, but does not appear to be efficiently transferred transplacentally. High C3-epimer concentrations in infancy are probably due to postnatal formation rather than fetal stores. © 2014 The Canadian Society of Clinical Chemists.
PubMed | University of Toronto, University of Guelph, Gamma Dynacare Medical Laboratories and Donnelly College
Type: | Journal: Biomaterials | Year: 2016
The increasing occurrence of antimicrobial resistance among bacteria is a global problem that requires the development of alternative techniques to eradicate these superbugs. Herein, we used a combination of thermosensitive biocompatible polymer and gold nanorods to specifically deliver, preserve and confine heat to the area of interest. Our data demonstrates that this technique can be used to kill both Gram positive and Gram negative antimicrobial resistant bacteria invitro. Our approach significantly reduces the antimicrobial resistant bacteria load in experimentally infected wounds by 98% without harming the surrounding tissues. More importantly, this polymer-nanocomposite can be prepared easily and applied to the wounds, can generate heat using a hand-held laser device, is safe for the operator, and does not have any adverse effects on the wound tissue and healing process.