scholarly journals Comparison of Two Bayesian Methods in Evaluation of the Absence of the Gold Standard Diagnostic Tests

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Taishun Li ◽  
Pei Liu
Keyword(s):  
Bayesian Methods ◽  
Gold Standard ◽  
Diagnostic Tests ◽  
Prior Distribution ◽  
Bayesian Model ◽  
Conditional Independence ◽  
Probabilistic Constraint ◽  
Conditional Covariance ◽  
Prior Constraint ◽  
Constraint Model

Objective. The Bayesian model plays an important role in diagnostic test evaluation in the absence of the gold standard, which used the external prior distribution of a parameter combined with sample data to yield the posterior distribution of the test characteristics. However, the correlation between diagnostic tests has always been a problem that cannot be ignored in the Bayesian model evaluation. This study will discuss how different Bayesian model, correlation scenarios, and prior distribution affect the outcome. Methods. The data analyzed in this study was gathered during studies of patients presenting to the Nanjing Chest Hospital with suspected tuberculosis. The diagnostic character of T-SPOT.Tb and KD38 tuberculosis antibody test were evaluated in different Bayesian model, and discharge diagnosis as a gold standard was used to verify the model results in the end. Result. The comparison of four models under the conditional independence situation found that Bayesian probabilistic constraint model was consistent with the Conditional Covariance Bayesian model. The results were mainly affected by prior information. The sensitivity and specificity of the two tests in Conditional Covariance Bayesian model in prior constraint situation were considerably higher than the Bayesian probabilistic constraint model in prior constraint situation. The results of the four models under the conditional dependence situation were similar to the conditional independence situation; pD was also negative with no prior constraint situation in both model Bayesian probabilistic constraint model and Conditional Covariance Bayesian model. The Deviance Information Criterion of Bayesian probabilistic constraint model was close to model Conditional Covariance Bayesian model, but pD of Conditional Covariance Bayesian model in Prior constraint situation (pD=2.40) was higher than the Bayesian probabilistic constraint model in Prior constraint situation (pD=1.66). Conclusion. The result of Conditional Covariance Bayesian model in prior constraint with conditional independence situation was closest to the result of gold standard evaluation in our data. Both of the two Bayesian methods are the feasible way for the evaluation of diagnostic test in the absence of the gold standard diagnostic. Prior source, priority number, and conditional dependencies should be considered in the method selection, the accuracy of posterior estimation mainly depending on the prior distribution.

Bayesian Applications in Auditory Research

2019 ◽  
Vol 62 (3) ◽  
pp. 577-586 ◽  
Author(s):  
Garnett P. McMillan ◽  
John B. Cannon
Keyword(s):  
Monte Carlo ◽  
Markov Chain ◽  
Bayesian Methods ◽  
Prior Distribution ◽  
Interim Analysis ◽  
Iterative Process ◽  
Bayes Theorem ◽  
Sound Therapy ◽  
The Many ◽  
Auditory Research

Purpose This article presents a basic exploration of Bayesian inference to inform researchers unfamiliar to this type of analysis of the many advantages this readily available approach provides. Method First, we demonstrate the development of Bayes' theorem, the cornerstone of Bayesian statistics, into an iterative process of updating priors. Working with a few assumptions, including normalcy and conjugacy of prior distribution, we express how one would calculate the posterior distribution using the prior distribution and the likelihood of the parameter. Next, we move to an example in auditory research by considering the effect of sound therapy for reducing the perceived loudness of tinnitus. In this case, as well as most real-world settings, we turn to Markov chain simulations because the assumptions allowing for easy calculations no longer hold. Using Markov chain Monte Carlo methods, we can illustrate several analysis solutions given by a straightforward Bayesian approach. Conclusion Bayesian methods are widely applicable and can help scientists overcome analysis problems, including how to include existing information, run interim analysis, achieve consensus through measurement, and, most importantly, interpret results correctly. Supplemental Material https://doi.org/10.23641/asha.7822592

The Spirit of Cromwell’s Rule

2018 ◽  
Author(s):  
Timothy McGrew
Keyword(s):  
Bayesian Methods ◽  
Bayesian Model ◽  
Bayesian Probability ◽  
Standard Textbook ◽  
Per Se

One of the central complaints about Bayesian probability is that it places no constraints on individual subjectivity in one’s initial probability assignments. Those sympathetic to Bayesian methods have responded by adding restrictions motivated by broader epistemic concerns about the possibility of changing one’s mind. This chapter explores some cases where, intuitively, a straightforward Bayesian model yields unreasonable results. Problems arise in these cases not because there is something wrong with the Bayesian formalism per se but because standard textbook illustrations teach us to represent our inferences in simplified ways that break down in extreme cases. It also explores some interesting limitations on the extent to which successive items of evidence ought to induce us to change our minds when certain screening conditions obtain.

A Bayesian Model to Assess a Binary Measurement System When No Gold Standard System Is Available

2011 ◽  
Vol 43 (1) ◽  
pp. 16-27 ◽  
Author(s):  
Daniel P. Beavers ◽  
James D. Stamey ◽  
B. Nebiyou Bekele
Keyword(s):  
Measurement System ◽  
Gold Standard ◽  
Bayesian Model ◽  
Standard System ◽  
No Gold Standard

scholarly journals Evaluation of two new rapid diagnostic tests (RDTs) for the diagnosis of malaria

2013 ◽  
Vol 5 (2) ◽  
pp. 11-15 ◽  
Author(s):  
Fahmida Jahan ◽  
Rubayet Elahi ◽  
Md. Khaja Mohiuddin ◽  
Md. Gulam Musawwir Khan ◽  
Mohammad Shafiul Alam ◽  
...  
Keyword(s):  
Predictive Value ◽  
Gold Standard ◽  
Diagnostic Tests ◽  
Rapid Diagnostic Tests ◽  
Accurate Diagnosis ◽  
The Other ◽  
Antibody Detection ◽  
Resource Limited Settings ◽  
Malaria Rdts ◽  
Resource Limited

Rapid diagnostic tests (RDTs) address the need for accurate diagnosis of malaria, particularly in resource limited settings. In this study, two malaria RDTs were compared with gold standard microscopy: On Site Pf/Pv test detecting Plasmodium falciparum-specific histidine rich protein-2 (Pf HR P2) and P. vivax-specific parasitic lactate dehydrogenase (pLDH) antigens; and SD Bioline anti-Pf/Pv test detecting anti-HR P2 and anti-pL DH antibodies for the diagnosis of P. falciparum and P. vivax infections, respectively. For OnSite test, the overall sensitivity was found 96.2% , specificity 98.2% , positive predictive value (PPV ) 98.2% , negative predictive value (NPV ) 96.4% and agreement with microscopy was found to be 0.94. On the other hand SD Bioline test, the overall sensitivity was 75.4%, specificity 83.7%, PPV 84.3% , NPV 74.5% and agreement with microscopy was 0.59. These data revealed that the R DT based on antigen detection (Onsite test) was more reliable than that based on the antibody detection (SD Bioline test).DOI: http://dx.doi.org/10.3329/bjmm.v5i2.16931 Bangladesh J Med Microbiol 2011; 05 (02): 11-15

scholarly journals Estimating the Gumbel-Barnett copula parameter of dependence

2018 ◽  
Vol 41 (1) ◽  
pp. 53-73 ◽  
Author(s):  
Jennyfer Portilla Yela ◽  
José Rafael Tovar Cuevas
Keyword(s):  
Maximum Likelihood ◽  
Simulation Study ◽  
Bayesian Methods ◽  
Prior Distribution ◽  
Empirical Evaluation ◽  
Bayesian Estimator ◽  
Dependence Structure ◽  
Type I ◽  
Copula Parameter

In this paper, we developed an empirical evaluation of four estimation procedures for the dependence parameter of the Gumbel-Barnett copula obtained from a Gumbel type I distribution. We used the maximum likelihood, moments and Bayesian methods and studied the performance of the estimates, assuming three dependence levels and 20 different sample sizes. For each method and scenario, a simulation study was conducted with 1000 runs and the quality of the estimator was evaluated using four different criteria. A Bayesian estimator assuming a Beta(a,b) as prior distribution, showed the best performance regardless the sample size and the dependence structure.

scholarly journals The blinding bug found in the eye

2019 ◽  
Vol 12 (1) ◽  
pp. bcr-2018-227194
Author(s):  
Manisha Agarwal ◽  
Lagan Paul ◽  
Chanda Gupta ◽  
Padmaja Kumari Rani
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Gold Standard ◽  
Diagnostic Tests ◽  
Surgical Intervention ◽  
Silicone Oil ◽  
Loss Of Vision ◽  
Antitubercular Treatment ◽  
Vitreous Sample ◽  
Silicone Oil Tamponade ◽  
Common Manifestation

Tubercular uveitis is a common manifestation of tuberculosis (TB) in TB-endemic countries. Due to lack of gold standard diagnostic tests for confirming intraocular TB, it is often either underdiagnosed or rarely over diagnosed. We report a case of a 28-year-old woman with diminution of vision in the left eye. She was started on antitubercular treatment (ATT) and steroids but she did not comply with the treatment. She developed progressive painful loss of vision consequently and was treated with vitrectomy and silicone oil tamponade. After a complete course of ATT, she recovered, salvaging of eye and restoration of some vision was possible. Mycobacterium tuberculosis is rarely demonstrated in the ocular fluid samples of the suspected cases of TB due to the paucibacillary nature of the disease. A vitreous sample can be obtained from these patients. Surgical intervention in the form of vitrectomy and silicone oil tamponade can help in avoiding enucleation/evisceration.

scholarly journals Toxin Detection by Cell Culture Neutralization Assay [CYT] and Toxin based EIA [Tox EIA] among Recurrent Episodes of CDI Diagnosed by PCR

2017 ◽  
Vol 4 (suppl_1) ◽  
pp. S395-S395
Author(s):  
Mini Kamboj ◽  
Tracy Mcmillen ◽  
Hoi Yan Chow ◽  
Jennifer Brite ◽  
N Esther Babady
Keyword(s):  
Gold Standard ◽  
Diagnostic Tests ◽  
Ad Hoc ◽  
Index Case ◽  
Extended Period ◽  
High Sensitivity ◽  
Neutralization Assay ◽  
Significant Implication ◽  
Stool Samples ◽  
Positive Recurrent

Abstract Background The Ad Hoc C. difficile surveillance working group defines recurrent C. difficile infection as a second episode occurring >8 weeks after the index case. Due to its high sensitivity, diagnosis of recurrent CDI by PCR is extremely challenging in patients who may have persistent, PCR detectable shedding of toxigenic C. difficile (TCD) for an extended period of time after treatment of the initial CDI episode. CYT, which detects C. difficile toxin antigen, is a cumbersome test to perform but is considered as the current clinical diagnostic gold standard for CDI diagnosis. Aim: To determine the CYT and Toxin A/B EIA positivity among patients with recurrent CDI episodes detected by PCR. We further characterized the performance of diagnostic tests based on whether the recurrent episode was a relapse or reinfection. Methods During a three month study period, CYT and Tox A/B EIA was performed on consecutive stool samples submitted from PCR positive recurrent episodes of CDI. For the purpose of this study, recurrence was defined as a second episode of CDI that occurred within 120 days from the most recent episode. MLST analysis was performed as previously described to characterize relapse and reinfection among the recurrent episodes (2). Results Thirty-five recurrent episodes occurred over the study period. 21/35 [60%] were positive by CYT and 12/35 [34%] by Tox A/B EIA. Among the recurrent CDI episodes, 16 (46%) were genotypical confirmed as relapse with the original infecting strain. Majority of these relapses were positive by CYT (81%) when compared with Tox EIA (43%). Among patients with geno typically confirmed reinfection (n = 8), CYT and EIA positivity was 63 % and 50 % respectively. For the remaining 11 episodes, TCD was not retrievable in culture, CYT and EIA positivity among this group was 27 % and 9 % respectively. Conclusion Forty percent of recurrent CDI episodes detected by PCR could not be confirmed by CYT. EIA missed 66 % of CYT positive recurrent CDI. The performance of CYT and EIA varied among recurrences due to relapse and reinfection. These results have significant implication for reporting of CDI HAI rates. Disclosures All authors: No reported disclosures.

Comparing Two Diagnostic Tests against the Same "Gold Standard" in the Same Sample

Biometrics ◽  
1997 ◽  
Vol 53 (1) ◽  
pp. 73 ◽  
Author(s):  
Daniel A. Bloch
Keyword(s):  
Gold Standard ◽  
Diagnostic Tests

scholarly journals Diagnostic test evaluation methodology: A systematic review of methods employed to evaluate diagnostic tests in the absence of gold standard – An update

PLoS ONE ◽  
2019 ◽  
Vol 14 (10) ◽  
pp. e0223832 ◽  
Author(s):  
Chinyereugo M. Umemneku Chikere ◽  
Kevin Wilson ◽  
Sara Graziadio ◽  
Luke Vale ◽  
A. Joy Allen
Keyword(s):  
Systematic Review ◽  
Diagnostic Test ◽  
Gold Standard ◽  
Diagnostic Tests ◽  
Evaluation Methodology ◽  
Test Evaluation ◽  
Diagnostic Test Evaluation
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