The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Jeffrey S. Ginsberg - One of the best experts on this subject based on the ideXlab platform.
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use of different d dimer levels to exclude venous thromboembolism depending on clinical Pretest probability
Journal of Thrombosis and Haemostasis, 2004Co-Authors: Loriann Linkins, Shannon M. Bates, Jeffrey S. Ginsberg, Clive KearonAbstract:Summary. Currently, the same D-dimer cut-off point is used to define a positive result for all patients with suspected venous thromboembolism, regardless of their Pretest probability. However, use of a relatively high D-dimer cut-off point (lower sensitivity) for those with a low clinical Pretest probability, and a low D-dimer cut-off point (higher sensitivity) for those with a high clinical Pretest probability, may be preferable. To determine if using three different D-dimer cut-off points according to low, moderate or high clinical Pretest probability has greater utility for exclusion of venous thromboembolism than using the same single D-dimer cut-off point in all patients. Data from a previously published study of 571 patients was used to identify the highest D-dimer cut-off point with a negative predictive value of at least 98% for the subgroup of patients with low and high Pretest probability. The D-dimer cut-off point for those with moderate clinical Pretest probability remained unchanged [0.5 fibrinogen equivalent units (FEU) l gm L )1 ]. Accuracy of D-dimer testing for venous thromboembolism using three cut-off points vs. one cut-off point was than determined. D-dimer cut-off points of 0.2 and 2.1 FEUl gm L )1 were selected for the high and low Pretest probability groups, respectively. When three Pretest probability-specific cut-off points were used instead of the previously determined single D-dimer cut-off point (0.5 FEU l gm L )1 ), sensitivity and negative predictive value were unchanged (95 and 98%, respectively), but specificity increased from 44.7 to 60.4% ( P< 0.001). This resulted in exclusion of venous thromboembolism in 80 additional patients. Use of three Pretest probability-specific D-dimer cut-off points rather than a single D-dimer cut-off point for all patients, has the potential to increase the utility of D-dimer testing for the diagnosis of venous thromboembolism.
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a latex d dimer reliably excludes venous thromboembolism
JAMA Internal Medicine, 2001Co-Authors: Shannon M. Bates, Anne Grandmaison, Ivy Naguit, Michael J Kovacs, Marilyn Johnston, Jeffrey S. GinsbergAbstract:Background D-Dimer, a cross-linked fibrin degradation product, has a high sensitivity in patients with suspected venous thrombosis. Traditional latex D-dimer assays, however, have not been sufficiently sensitive to exclude venous thromboembolism. Methods To determine the clinical utility of a latex D-dimer assay (MDA D-Dimer; Organon Teknika Corporation, Durham, NC) in patients with suspected venous thromboembolism, we conducted a retrospective cohort study involving 595 unselected patients at 4 tertiary care hospitals. Patients had blood drawn for performance of the D-dimer assay and underwent objective testing for venous thromboembolism. Pretest probability was determined using validated models in 571 patients. Patients were classified as venous thromboembolism positive or negative according to results of objective tests and 3-month follow-up. The sensitivities, specificities, predictive values, and negative likelihood ratios of the assay were calculated for all patients and for subgroups of patients with known cancer or a low, moderate, or high Pretest probability of venous thromboembolism. Results The prevalence of venous thromboembolism was 19.0% (113/595). Of those who had a Pretest probability assessment, 35.9% had a low Pretest probability, 49.7% a moderate Pretest probability, and 14.4% a high Pretest probability. Using a discriminant value of 0.50 µg fibrinogen equivalent units per milliliter, the assay showed an overall sensitivity of 96%, a negative predictive value of 98%, a specificity of 45%, and a negative likelihood ratio of 0.09. In patients with a low or moderate Pretest probability, the sensitivity, negative predictive value, and negative likelihood ratio were 97%, 99%, and 0.07, respectively. Conclusions The MDA D-Dimer assay is the first latex agglutination assay with sufficient sensitivity to be clinically useful in the exclusion of venous thromboembolism. A negative result has the potential to be used as the sole test to exclude venous thromboembolism in patients with a low or moderate Pretest probability of disease.
Shannon M. Bates - One of the best experts on this subject based on the ideXlab platform.
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use of different d dimer levels to exclude venous thromboembolism depending on clinical Pretest probability
Journal of Thrombosis and Haemostasis, 2004Co-Authors: Loriann Linkins, Shannon M. Bates, Jeffrey S. Ginsberg, Clive KearonAbstract:Summary. Currently, the same D-dimer cut-off point is used to define a positive result for all patients with suspected venous thromboembolism, regardless of their Pretest probability. However, use of a relatively high D-dimer cut-off point (lower sensitivity) for those with a low clinical Pretest probability, and a low D-dimer cut-off point (higher sensitivity) for those with a high clinical Pretest probability, may be preferable. To determine if using three different D-dimer cut-off points according to low, moderate or high clinical Pretest probability has greater utility for exclusion of venous thromboembolism than using the same single D-dimer cut-off point in all patients. Data from a previously published study of 571 patients was used to identify the highest D-dimer cut-off point with a negative predictive value of at least 98% for the subgroup of patients with low and high Pretest probability. The D-dimer cut-off point for those with moderate clinical Pretest probability remained unchanged [0.5 fibrinogen equivalent units (FEU) l gm L )1 ]. Accuracy of D-dimer testing for venous thromboembolism using three cut-off points vs. one cut-off point was than determined. D-dimer cut-off points of 0.2 and 2.1 FEUl gm L )1 were selected for the high and low Pretest probability groups, respectively. When three Pretest probability-specific cut-off points were used instead of the previously determined single D-dimer cut-off point (0.5 FEU l gm L )1 ), sensitivity and negative predictive value were unchanged (95 and 98%, respectively), but specificity increased from 44.7 to 60.4% ( P< 0.001). This resulted in exclusion of venous thromboembolism in 80 additional patients. Use of three Pretest probability-specific D-dimer cut-off points rather than a single D-dimer cut-off point for all patients, has the potential to increase the utility of D-dimer testing for the diagnosis of venous thromboembolism.
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a latex d dimer reliably excludes venous thromboembolism
JAMA Internal Medicine, 2001Co-Authors: Shannon M. Bates, Anne Grandmaison, Ivy Naguit, Michael J Kovacs, Marilyn Johnston, Jeffrey S. GinsbergAbstract:Background D-Dimer, a cross-linked fibrin degradation product, has a high sensitivity in patients with suspected venous thrombosis. Traditional latex D-dimer assays, however, have not been sufficiently sensitive to exclude venous thromboembolism. Methods To determine the clinical utility of a latex D-dimer assay (MDA D-Dimer; Organon Teknika Corporation, Durham, NC) in patients with suspected venous thromboembolism, we conducted a retrospective cohort study involving 595 unselected patients at 4 tertiary care hospitals. Patients had blood drawn for performance of the D-dimer assay and underwent objective testing for venous thromboembolism. Pretest probability was determined using validated models in 571 patients. Patients were classified as venous thromboembolism positive or negative according to results of objective tests and 3-month follow-up. The sensitivities, specificities, predictive values, and negative likelihood ratios of the assay were calculated for all patients and for subgroups of patients with known cancer or a low, moderate, or high Pretest probability of venous thromboembolism. Results The prevalence of venous thromboembolism was 19.0% (113/595). Of those who had a Pretest probability assessment, 35.9% had a low Pretest probability, 49.7% a moderate Pretest probability, and 14.4% a high Pretest probability. Using a discriminant value of 0.50 µg fibrinogen equivalent units per milliliter, the assay showed an overall sensitivity of 96%, a negative predictive value of 98%, a specificity of 45%, and a negative likelihood ratio of 0.09. In patients with a low or moderate Pretest probability, the sensitivity, negative predictive value, and negative likelihood ratio were 97%, 99%, and 0.07, respectively. Conclusions The MDA D-Dimer assay is the first latex agglutination assay with sufficient sensitivity to be clinically useful in the exclusion of venous thromboembolism. A negative result has the potential to be used as the sole test to exclude venous thromboembolism in patients with a low or moderate Pretest probability of disease.
Agustín Orihuela - One of the best experts on this subject based on the ideXlab platform.
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Assessment of the Impact of an Animal Welfare Educational Course with First Grade Children in Rural Schools in the State of Morelos, Mexico
Early Childhood Education Journal, 2010Co-Authors: Virginio Aguirre, Agustín OrihuelaAbstract:The purpose of this study was to evaluate if an educational package used for animal welfare teaching would have significant effects on the knowledge of first grade children in a rural area of Mexico. The research was conducted with 276 students in six public schools. In the experimental group, 177 children participated in a 10 week-long animal welfare education program that covered ten one-hour animal welfare topics. The control group, consisting of 99 children, did not receive the course. There were no significant differences ( P > 0.05) between Pretests of the experimental and control schools (ANOVA). However, a significant effect of the program on the children’s knowledge was found when the results of the posttest were analyzed using the Pretest as a covariate (ANCOVA). Furthermore, the correct responses of the children exposed to the Animal Welfare program were on average 78% richer in concepts compared to responses from children in the control group. These results contribute to the growing body of research literature on the relationship between children and animals in humane education, suggesting that first grade children living in moderate economic conditions can assimilate animal welfare concepts.
Clive Kearon - One of the best experts on this subject based on the ideXlab platform.
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use of different d dimer levels to exclude venous thromboembolism depending on clinical Pretest probability
Journal of Thrombosis and Haemostasis, 2004Co-Authors: Loriann Linkins, Shannon M. Bates, Jeffrey S. Ginsberg, Clive KearonAbstract:Summary. Currently, the same D-dimer cut-off point is used to define a positive result for all patients with suspected venous thromboembolism, regardless of their Pretest probability. However, use of a relatively high D-dimer cut-off point (lower sensitivity) for those with a low clinical Pretest probability, and a low D-dimer cut-off point (higher sensitivity) for those with a high clinical Pretest probability, may be preferable. To determine if using three different D-dimer cut-off points according to low, moderate or high clinical Pretest probability has greater utility for exclusion of venous thromboembolism than using the same single D-dimer cut-off point in all patients. Data from a previously published study of 571 patients was used to identify the highest D-dimer cut-off point with a negative predictive value of at least 98% for the subgroup of patients with low and high Pretest probability. The D-dimer cut-off point for those with moderate clinical Pretest probability remained unchanged [0.5 fibrinogen equivalent units (FEU) l gm L )1 ]. Accuracy of D-dimer testing for venous thromboembolism using three cut-off points vs. one cut-off point was than determined. D-dimer cut-off points of 0.2 and 2.1 FEUl gm L )1 were selected for the high and low Pretest probability groups, respectively. When three Pretest probability-specific cut-off points were used instead of the previously determined single D-dimer cut-off point (0.5 FEU l gm L )1 ), sensitivity and negative predictive value were unchanged (95 and 98%, respectively), but specificity increased from 44.7 to 60.4% ( P< 0.001). This resulted in exclusion of venous thromboembolism in 80 additional patients. Use of three Pretest probability-specific D-dimer cut-off points rather than a single D-dimer cut-off point for all patients, has the potential to increase the utility of D-dimer testing for the diagnosis of venous thromboembolism.
Shannon E. Coulter - One of the best experts on this subject based on the ideXlab platform.
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Using the retrospective Pretest to get usable, indirect evidence of student learning
Assessment & Evaluation in Higher Education, 2011Co-Authors: Shannon E. CoulterAbstract:Minimal evidence exists regarding the retrospective Pretest’s effectiveness as a tool to obtain usable, indirect evidence of student learning in open admissions institutions. The researcher conducted this study to determine if a retrospective Pretest more accurately detected a change in students’ knowledge compared to a conventional Pretest–posttest. The researcher designed a 17‐item inventory covering course objectives, and students were randomly assigned to either a retrospective Pretest (referred to as post‐then) or a conventional Pretest–posttest group. Findings indicated that participants in the post‐then group reported a greater change in knowledge compared to the conventional group. This finding supported the use of the retrospective Pretest as a tool for getting usable, indirect evidence of student learning. Future research needs to examine response effect, alternative ways of calculating treatment effect and the confounding influences of other perceptual variables.
