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Richard Body - One of the best experts on this subject based on the ideXlab platform.
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rapid rule out of acute myocardial infarction with a single high sensitivity cardiac troponin t measurement below the Limit of Detection a collaborative meta analysis
Annals of Internal Medicine, 2017Co-Authors: John W Pickering, Edward Carlton, Martin Than, Louise Cullen, Sally Aldous, Ewoud Ter Avest, Richard Body, P Collinson, Anne Marie Dupuy, Ulf EkelundAbstract:Background: High-sensitivity assays for cardiac troponin T (hs-cTnT) are sometimes used to rapidly rule out acute myocardial infarction (AMI). Purpose: To estimate the ability of a single hs-cTnT concentration below the Limit of Detection (<0.005 µg/L) and a nonischemic electrocardiogram (ECG) to rule out AMI in adults presenting to the emergency department (ED) with chest pain. Data Sources: EMBASE and MEDLINE without language restrictions (1 January 2008 to 14 December 2016). Study Selection: Cohort studies involving adults presenting to the ED with possible acute coronary syndrome in whom an ECG and hs-cTnT measurements were obtained and AMI outcomes adjudicated during initial hospitalization. Data Extraction: Investigators of studies provided data on the number of low-risk patients (no new ischemia on ECG and hs-cTnT measurements <0.005 µg/L) and the number who had AMI during hospitalization (primary outcome) or a major adverse cardiac event (MACE) or death within 30 days (secondary outcomes), by risk classification (low or not low risk). Two independent epidemiologists rated risk of bias of studies. Data Synthesis: of 9241 patients in 11 cohort studies, 2825 (30.6%) were classified as low risk. Fourteen (0.5%) low-risk patients had AMI. Sensitivity of the risk classification for AMI ranged from 87.5% to 100% in individual studies. Pooled estimated sensitivity was 98.7% (95% CI, 96.6% to 99.5%). Sensitivity for 30-day MACEs ranged from 87.9% to 100%; pooled sensitivity was 98.0% (CI, 94.7% to 99.3%). No low-risk patients died. Limitation: Few studies, variation in timing and methods of reference standard troponin tests, and heterogeneity of risk and prevalence of AMI across studies. Conclusion: A single hs-cTnT concentration below the Limit of Detection in combination with a nonischemic ECG may successfully rule out AMI in patients presenting to EDs with possible emergency acute coronary syndrome. Primary Funding Source: Emergency Care Foundation.
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one shot to rule out does the Limit of Detection of a high sensitivity troponin assay hit the mark
Clinical Chemistry, 2017Co-Authors: Richard Body, Charles ReynardAbstract:In this special issue of the journal there are 4 articles examining the value of high-sensitivity cardiac troponin (hs-cTn)4 cutoffs set below the conventional 99th percentile upper reference Limit to rule out acute myocardial infarction (AMI) with a single blood test at the time of arrival in the emergency department. This strategy could obviate the need for serial blood sampling in a potentially substantial proportion of patients presenting with symptoms that are compatible with an acute coronary syndrome. The use of this method would also overcome one of the key Limitations of cardiac troponin as a biomarker and could help to decrease overcrowding of hospitals and emergency departments, which is a growing problem internationally. The potential use of unconventionally low cutoffs may thus be one of the most clinically important advantages of hs-cTn assays. With the hs-cTnT assay (Roche Diagnostics Elecsys, 99th percentile 14 ng/L), this potential benefit was realized as early as 2011, and much of the existing evidence with this assay has focused on its use for ruling out a diagnosis of AMI. A single-center prospective study reported that, using the admission blood sample, the assay had 100% sensitivity for AMI when the cutoff was set at the Limit of blank (3 ng/L) (1). Using this cutoff, 28% of patients could have had AMI immediately ruled out. A large retrospective study of 14636 patients later confirmed that a threshold of 5 ng/L [the Limit of Detection (LOD)] could also yield a very high negative predictive value (NPV) when applied to patients with no electrocardiogram (ECG) ischemia (2). Further studies have added weight to the suggestion that AMI can be considered ruled out in patients with an hs-cTnT <5 ng/L and no ECG ischemia. A prospective study of 463 patients showed that by use of this strategy 17% …
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high sensitivity cardiac troponin t concentrations below the Limit of Detection to exclude acute myocardial infarction a prospective evaluation
Clinical Chemistry, 2015Co-Authors: Martin Than, Louise Cullen, Richard Body, Gillian Burrows, Simon Carley, Allan S Jaffe, Philip S LewisAbstract:Background Initial reports suggest that concentrations of high-sensitivity cardiac troponin T (hs-cTnT) (Roche Diagnostics Elecsys®) below the Limit of blank (LoB) (3 ng/L) or Limit of Detection (LoD) (5 ng/L) of the assay have almost 100% negative predictive value (NPV) for acute myocardial infarction (AMI), particularly among patients without electrocardiograph (ECG) evidence of ischemia. We aimed to prospectively validate those findings. Methods We included adults presenting to the emergency department with suspected cardiac chest pain. Standard troponin T (cTnT) and hs-cTnT (both Roche Elecsys) were tested in samples drawn on arrival. The primary outcome was AMI, adjudicated by 2 investigators on the basis of clinical data and ≥12-h cTnT testing. We also evaluated diagnostic performance when AMI was readjudicated on the basis of hs-cTnT (≥12-h) concentrations. Results of 463 patients included, 79 (17.1%) had AMI. Twenty-four patients (5.2%) had hs-cTnT concentrations below the LoB, although none had AMI. Ninety-six patients (20.7%) had hs-cTnT concentrations below the LoD, 1 of whom had AMI. Thus, diagnostic sensitivity was 98.7% (95% CI 87.5%–98.6%) and NPV was 99.0% (95% CI 94.3%–100.0%). of the 17.3% (n = 80) patients with hs-cTnT below the LoD and no ECG ischemia, none had AMI. Thus, diagnostic sensitivity was 100.0% (95% CI 95.4%–100.0%) and NPV was 100.0% (95% CI 95.5%–100.0%). Sensitivity and NPV were maintained when AMI was readjudicated on the basis of hs-cTnT. Conclusions Our findings confirm that patients with normal ECG and undetectable hs-cTnT at presentation have a very low probability of AMI, although the proportion of patients affected was smaller than in previous research.
Pedro Machado - One of the best experts on this subject based on the ideXlab platform.
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calculating the ankylosing spondylitis disease activity score if the conventional c reactive protein level is below the Limit of Detection or if high sensitivity c reactive protein is used an analysis in the desir cohort
Arthritis & Rheumatism, 2015Co-Authors: Pedro Machado, Robert Landewe, Floris A Van Gaalen, V Navarrocompan, Christian Roux, Desiree Van Der HeijdeAbstract:Objective The Ankylosing Spondylitis Disease Activity Score (ASDAS) is a composite measure of disease activity in axial spondyloarthritis. The aims of this study were to determine the most appropriate method for calculating the ASDAS using the C-reactive protein (CRP) level when the conventional CRP level was below the Limit of Detection, to determine how low CRP values obtained by high-sensitivity CRP (hsCRP) measurement influence ASDAS-CRP results, and to test agreement between different ASDAS formulae. Methods Patients with axial spondyloarthritis who had a conventional CRP level below the Limit of Detection (5 mg/liter) were selected (n = 257). The ASDAS–conventional CRP with 11 different imputations for the conventional CRP value (range 0–5 mg/liter, at 0.5-mg/liter intervals) was calculated. The ASDAS-hsCRP and ASDAS using the erythrocyte sedimentation rate (ESR) were also calculated. Agreement between the ASDAS formulae was tested. Results The ASDAS-hsCRP showed better agreement with the ASDAS-CRP calculated using the conventional CRP imputation values of 1.5 and 2.0 mg/liter and with the ASDAS-ESR than with other imputed formulae. Disagreement occurred mainly in lower disease activity states (inactive/moderate disease activity). When the CRP value was <2 mg/liter, the resulting ASDAS-CRP scores may have been inappropriately low. Conclusion When the conventional CRP level is below the Limit of Detection or when the hsCRP level is <2 mg/liter, the constant value of 2 mg/liter should be used to calculate the ASDAS-CRP score. There is good agreement between the ASDAS-hsCRP and ASDAS-ESR; however, formulae are not interchangeable.
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brief report calculating the ankylosing spondylitis disease activity score if the conventional c reactive protein level is below the Limit of Detection or if high sensitivity c reactive protein is used an analysis in the desir cohort
Arthritis & Rheumatism, 2015Co-Authors: Pedro Machado, Robert Landewe, V Navarrocompan, Christian Roux, Floris Van Gaalen, Desiree Van Der HeijdeAbstract:Objective The Ankylosing Spondylitis Disease Activity Score (ASDAS) is a composite measure of disease activity in axial spondyloarthritis. The aims of this study were to determine the most appropriate method for calculating the ASDAS using the C-reactive protein (CRP) level when the conventional CRP level was below the Limit of Detection, to determine how low CRP values obtained by high-sensitivity CRP (hsCRP) measurement influence ASDAS-CRP results, and to test agreement between different ASDAS formulae. Methods Patients with axial spondyloarthritis who had a conventional CRP level below the Limit of Detection (5 mg/liter) were selected (n = 257). The ASDAS–conventional CRP with 11 different imputations for the conventional CRP value (range 0–5 mg/liter, at 0.5-mg/liter intervals) was calculated. The ASDAS-hsCRP and ASDAS using the erythrocyte sedimentation rate (ESR) were also calculated. Agreement between the ASDAS formulae was tested. Results The ASDAS-hsCRP showed better agreement with the ASDAS-CRP calculated using the conventional CRP imputation values of 1.5 and 2.0 mg/liter and with the ASDAS-ESR than with other imputed formulae. Disagreement occurred mainly in lower disease activity states (inactive/moderate disease activity). When the CRP value was <2 mg/liter, the resulting ASDAS-CRP scores may have been inappropriately low. Conclusion When the conventional CRP level is below the Limit of Detection or when the hsCRP level is <2 mg/liter, the constant value of 2 mg/liter should be used to calculate the ASDAS-CRP score. There is good agreement between the ASDAS-hsCRP and ASDAS-ESR; however, formulae are not interchangeable.
Jeanmichel Mermet - One of the best experts on this subject based on the ideXlab platform.
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a study of the relation between the Limit of Detection and the Limit of quantitation in inductively coupled plasma spectrochemistry
Spectrochimica Acta Part B: Atomic Spectroscopy, 1997Co-Authors: Madeleine Carre, S Excoffier, Jeanmichel MermetAbstract:The Limit of quantitation based on a repeatability threshold concept is compared with the Limit of Detection in induction coupled plasma atomic emission spectrometry (ICP-AES) and induction coupled plasma mass spectrometry (ICP-MS). A 5%-based Limit of quantitation would normally correspond to 10 times the 3-σ based Limit of Detection. However, because of a possible lack of linearity of the calibration graph at low concentrations, some additional noise not taken into consideration and the possible use of time-correlated multichannel Detection, this ratio of 10 cannot be used in every case. It is suggested that a suitable way of determining the Limit of quantitation is to establish the plot of the percentage relative standard deviation (RSD) of the net signal as a function of the concentration in a range from the Limit of Detection to 50 times this Limit.
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simultaneous measurements of signal and background in inductively coupled plasma atomic emission spectrometry effects on precision Limit of Detection and Limit of quantitation
Spectrochimica Acta Part B: Atomic Spectroscopy, 1996Co-Authors: Emmanuelle Poussel, Jeanmichel MermetAbstract:Abstract Use of simultaneous measurements of the line intensity and the off-peak background intensity results in a significant improvement of repeatability at low concentrations, the Limit of Detection and the Limit of quantitation in inductively coupled plasma atomic emission spectrometry. Simultaneous measurements have been performed using an echellebased dispersive system equipped with a custom segmented-array charge coupled device detector. Correlation between background signals, and shape of the curve of the RSD of the net signal as a function of the concentration is studied from both a theoretical and practical aspect. Concepts of Limit of Detection and Limit of quantitation are discussed both in terms of RSD of the net signal and correlation. Results have been obtained using the Ba II 455 nm line in the visible region and the Ni II 231 nm line in the UV region. Improvements in the Limit of Detection and Limit of quantitation are up to a factor of 10 and are in good agreement with theoretical values. The main Limitation of the procedure is related to the accuracy of the background correction.
Desiree Van Der Heijde - One of the best experts on this subject based on the ideXlab platform.
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calculating the ankylosing spondylitis disease activity score if the conventional c reactive protein level is below the Limit of Detection or if high sensitivity c reactive protein is used an analysis in the desir cohort
Arthritis & Rheumatism, 2015Co-Authors: Pedro Machado, Robert Landewe, Floris A Van Gaalen, V Navarrocompan, Christian Roux, Desiree Van Der HeijdeAbstract:Objective The Ankylosing Spondylitis Disease Activity Score (ASDAS) is a composite measure of disease activity in axial spondyloarthritis. The aims of this study were to determine the most appropriate method for calculating the ASDAS using the C-reactive protein (CRP) level when the conventional CRP level was below the Limit of Detection, to determine how low CRP values obtained by high-sensitivity CRP (hsCRP) measurement influence ASDAS-CRP results, and to test agreement between different ASDAS formulae. Methods Patients with axial spondyloarthritis who had a conventional CRP level below the Limit of Detection (5 mg/liter) were selected (n = 257). The ASDAS–conventional CRP with 11 different imputations for the conventional CRP value (range 0–5 mg/liter, at 0.5-mg/liter intervals) was calculated. The ASDAS-hsCRP and ASDAS using the erythrocyte sedimentation rate (ESR) were also calculated. Agreement between the ASDAS formulae was tested. Results The ASDAS-hsCRP showed better agreement with the ASDAS-CRP calculated using the conventional CRP imputation values of 1.5 and 2.0 mg/liter and with the ASDAS-ESR than with other imputed formulae. Disagreement occurred mainly in lower disease activity states (inactive/moderate disease activity). When the CRP value was <2 mg/liter, the resulting ASDAS-CRP scores may have been inappropriately low. Conclusion When the conventional CRP level is below the Limit of Detection or when the hsCRP level is <2 mg/liter, the constant value of 2 mg/liter should be used to calculate the ASDAS-CRP score. There is good agreement between the ASDAS-hsCRP and ASDAS-ESR; however, formulae are not interchangeable.
Desiree Van Der Heijde - One of the best experts on this subject based on the ideXlab platform.
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brief report calculating the ankylosing spondylitis disease activity score if the conventional c reactive protein level is below the Limit of Detection or if high sensitivity c reactive protein is used an analysis in the desir cohort
Arthritis & Rheumatism, 2015Co-Authors: Pedro Machado, Robert Landewe, V Navarrocompan, Christian Roux, Floris Van Gaalen, Desiree Van Der HeijdeAbstract:Objective The Ankylosing Spondylitis Disease Activity Score (ASDAS) is a composite measure of disease activity in axial spondyloarthritis. The aims of this study were to determine the most appropriate method for calculating the ASDAS using the C-reactive protein (CRP) level when the conventional CRP level was below the Limit of Detection, to determine how low CRP values obtained by high-sensitivity CRP (hsCRP) measurement influence ASDAS-CRP results, and to test agreement between different ASDAS formulae. Methods Patients with axial spondyloarthritis who had a conventional CRP level below the Limit of Detection (5 mg/liter) were selected (n = 257). The ASDAS–conventional CRP with 11 different imputations for the conventional CRP value (range 0–5 mg/liter, at 0.5-mg/liter intervals) was calculated. The ASDAS-hsCRP and ASDAS using the erythrocyte sedimentation rate (ESR) were also calculated. Agreement between the ASDAS formulae was tested. Results The ASDAS-hsCRP showed better agreement with the ASDAS-CRP calculated using the conventional CRP imputation values of 1.5 and 2.0 mg/liter and with the ASDAS-ESR than with other imputed formulae. Disagreement occurred mainly in lower disease activity states (inactive/moderate disease activity). When the CRP value was <2 mg/liter, the resulting ASDAS-CRP scores may have been inappropriately low. Conclusion When the conventional CRP level is below the Limit of Detection or when the hsCRP level is <2 mg/liter, the constant value of 2 mg/liter should be used to calculate the ASDAS-CRP score. There is good agreement between the ASDAS-hsCRP and ASDAS-ESR; however, formulae are not interchangeable.
