scholarly journals P.051 Do clinical confounders to the neurological examination modify the diagnostic accuracy of CT-angiography for death by neurological criteria/brain death?

2021 ◽  
Vol 48 (s3) ◽  
pp. S33-S33
Author(s):  
J Neves Briard ◽  
R Nitulescu ◽  
É Lemoine ◽  
S English ◽  
L McIntyre ◽  
...  
Keyword(s):  
Systematic Review ◽  
Diagnostic Accuracy ◽  
Ct Angiography ◽  
Neurological Examination ◽  
Meta Analysis ◽  
Bayesian Hierarchical Model ◽  
Statistical Uncertainty ◽  
Bayesian Hierarchical ◽  
Ancillary Test ◽  
The Impact

Background: CT-angiography is an ancillary test used to diagnose death by neurological criteria (DNC), notably in cases of unreliable neurological examinations due to clinical confounders. We studied whether clinical confounders to the neurological examination modified CT-angiography diagnostic accuracy. Methods: Systematic review and meta-analysis of studies including deeply comatose patients undergoing DNC ancillary testing. We estimated pooled sensitivities and specificities using a Bayesian hierarchical model, including data on CT-angiography (4-point, 7-point, 10-point scales, and no intracranial flow), and performing a subgroup analysis on clinical confounders to the reference neurological examination. Results: Of 40 studies included in the meta-analysis, 7 involve CT-angiography (n=586). There was no difference between subgroups (Table). The degree of uncertainty involving sensitivity estimates was high in both subgroups. Conclusions: Statistical uncertainty in diagnostic accuracy estimates preclude any conclusion regarding the impact of clinical confounders on CT-angiography diagnostic accuracy. Further research is required to validate CT-angiography as an accurate ancillary test for DNC. Table. Pooled sensitivities and specificities of CT-angiography for death by neurological criteria

scholarly journals Diagnostic accuracy of refractometer and Brix refractometer to assess failure of passive transfer in calves: protocol for a systematic review and meta-analysis

2016 ◽  
Vol 17 (1) ◽  
pp. 3-8 ◽  
Author(s):  
S. Buczinski ◽  
G. Fecteau ◽  
M. Chigerwe ◽  
J. M. Vandeweerd
Keyword(s):  
Systematic Review ◽  
Diagnostic Accuracy ◽  
Meta Analysis ◽  
Passive Transfer ◽  
Standard Test ◽  
Passive Immunity ◽  
Test Accuracy ◽  
Reference Standard ◽  
Review Protocol ◽  
The Impact

AbstractCalves are highly dependent of colostrum (and antibody) intake because they are born agammaglobulinemic. The transfer of passive immunity in calves can be assessed directly by dosing immunoglobulin G (IgG) or by refractometry or Brix refractometry. The latter are easier to perform routinely in the field. This paper presents a protocol for a systematic review meta-analysis to assess the diagnostic accuracy of refractometry or Brix refractometry versus dosage of IgG as a reference standard test. With this review protocol we aim to be able to report refractometer and Brix refractometer accuracy in terms of sensitivity and specificity as well as to quantify the impact of any study characteristic on test accuracy.

scholarly journals A hybrid Bayesian hierarchical model combining cohort and case–control studies for meta-analysis of diagnostic tests: Accounting for partial verification bias

2016 ◽  
Vol 25 (6) ◽  
pp. 3015-3037 ◽  
Author(s):  
Xiaoye Ma ◽  
Yong Chen ◽  
Stephen R Cole ◽  
Haitao Chu
Keyword(s):  
Diagnostic Accuracy ◽  
Hierarchical Model ◽  
Meta Analysis ◽  
Bayesian Hierarchical Model ◽  
Case Control ◽  
Disease Prevalence ◽  
Case Control Studies ◽  
Verification Bias ◽  
Bayesian Hierarchical ◽  
Model Combining

To account for between-study heterogeneity in meta-analysis of diagnostic accuracy studies, bivariate random effects models have been recommended to jointly model the sensitivities and specificities. As study design and population vary, the definition of disease status or severity could differ across studies. Consequently, sensitivity and specificity may be correlated with disease prevalence. To account for this dependence, a trivariate random effects model had been proposed. However, the proposed approach can only include cohort studies with information estimating study-specific disease prevalence. In addition, some diagnostic accuracy studies only select a subset of samples to be verified by the reference test. It is known that ignoring unverified subjects may lead to partial verification bias in the estimation of prevalence, sensitivities, and specificities in a single study. However, the impact of this bias on a meta-analysis has not been investigated. In this paper, we propose a novel hybrid Bayesian hierarchical model combining cohort and case–control studies and correcting partial verification bias at the same time. We investigate the performance of the proposed methods through a set of simulation studies. Two case studies on assessing the diagnostic accuracy of gadolinium-enhanced magnetic resonance imaging in detecting lymph node metastases and of adrenal fluorine-18 fluorodeoxyglucose positron emission tomography in characterizing adrenal masses are presented.

scholarly journals The impact of emerging Plasmodium knowlesi on accurate diagnosis by light microscopy: a systematic review and modelling analysis

2021 ◽  
Author(s):  
John H. Huber ◽  
Margaret Elliott ◽  
Cristian Koepfli ◽  
T. Alex Perkins
Keyword(s):  
Systematic Review ◽  
Light Microscopy ◽  
Latent Class ◽  
Plasmodium Knowlesi ◽  
Meta Analysis ◽  
Latent Class Model ◽  
Malaria Diagnosis ◽  
Bayesian Hierarchical ◽  
Highly Correlated ◽  
The Impact

ABSTRACTBackgroundThe five Plasmodium spp. that cause human malaria appear similar under light microscopy, which raises the possibility that misdiagnosis could routinely occur in clinical settings. Assessing the extent of misdiagnosis is of particular importance for monitoring P. knowlesi, which co-circulates with the other Plasmodium spp.MethodsWe performed a systematic review and meta-analysis of studies comparing the performance of microscopy and PCR for diagnosing malaria in settings with co-circulation of the five Plasmodium spp. We assessed the extent to which co-circulation of Plasmodium parasites affects diagnostic outcomes. We fit a Bayesian hierarchical latent class model to estimate variation in microscopy sensitivity and specificity.ResultsMean sensitivity of microscopy was low, yet highly variable across Plasmodium spp., ranging from 41.7% (95% CI: 22.8 – 64.1%) for P. falciparum and 40.3% (22.0 – 61.5%) for P. vivax to 0.119% (0.0121 – 0.640%) for P. knowlesi, 7.57% (2.66 – 22.0%) for P. malariae, and 0.180% (0.00491 – 1.21%) for P. ovale. Observed PCR prevalence was positively correlated with estimated microscopic sensitivity and negatively correlated with estimated microscopic specificity, though the strength of the associations varied by species.ConclusionsOur analysis suggests that co-circulation of Plasmodium spp. undermines the accuracy of microscopy. Sensitivity was considerably lower for P. knowlesi, P. malariae, and P. ovale. The negative association between specificity and PCR prevalence imply that less frequently encountered species may be misdiagnosed as more frequently encountered species. Together, these results suggest that the burden of P. knowlesi, P. malariae, and P. ovale may be underappreciated in a clinical setting.SummaryCo-circulation of Plasmodium species parasites may limit the accuracy of malaria diagnosis by light microscopy. Variation in performance of light microscopy is highly correlated with the prevalence of the parasites in the epidemiological setting.

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