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Acurracy assessment of four diagnostic tests for the detection of Giardia and Cryptosporidium in the absence of gold standard: a Bayesian approach

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dc.contributor.authorPalomares Velosa, Jairo Enrique, author
dc.contributor.authorSalman, Mo D., advisor
dc.contributor.authorBallweber, Lora, committee member
dc.contributor.authorLappin, Michael, committee member
dc.date.accessioned2007-01-03T06:23:22Z
dc.date.available2007-01-03T06:23:22Z
dc.date.issued2014
dc.description.abstractGiardia and Cryptosporidium are important parasites that cause gastrointestinal disease in numerous animal species including dogs and cats. The accurate diagnostic of this diseases is cucial for the aplication of preventive measures and precise treatment. Estimation of test accuraccy is not difficult when a reference test (gold standard) is available. However, when a gold standard test is not available the Bayesian Latent Class (BLC) Analysis is an effective analytical tool for the estimation of diagnostic accuracy. The aim of this study was to estimate the sensitivity (Se) and specificity (Sp) of four commercial diagnostic kits using BLC. The four diagnostic tests were (1) Merifluor®Direct Fluorecence Antigen (DFA; Giardia/Cryptosporidium; Meridian Diagnostics, Inc., Cincinnati, Ohio), (2) IVD®DFA (Giardia/Cryptosporidium; IDV Research Inc., Carlsbad, CA), (3) IVD Microwell ELISA® (Giardia ; IDV Research Inc., Carlsbad, CA), (4) and IDEXX SNAP® (Giardia ; IDEXX Laboratories Inc., Westbrook, ME). The results from 201 laboratory analysed samples, the prior distributions elicited from three experts, and the consistency of samples as splitting covariate were used as inputs for the BCL models. The estimated Se and Sp of the tests were 87.7% and 97.3% (Merifluor-Cryptosporidium), 68.0% and 99.1% (IVD-Cryptosporidium), 93.6% and 97.9% (Merifluor-Giardia), 96.1% and 97.9% (IVD-Giardia), 86.0% and 98.2% (ELISA-Giardia), and 84.8% and 98.0% (SNAP-Giardia) respectively. The prevalence for non-diarrheic versus diarrheic samples were 2.3% and 4.8% (Cryptosporidium), and 6.9% and 13.5% (Giardia) respectively. We were able to use BLC to assess the sensitivity and specificity of the four commercial diagnostic tests. We ran 36 models and used objective indicators of the performances of the models to choose the best model for estimation of parameters. The results of the study indicated that Merifluor, IVD, and ELISA are equally suitable as diagnostic tests for detection of Giardia. For detection of Cryptosporidium, Merifluor was more accurate than the IVD test.
dc.format.mediumborn digital
dc.format.mediummasters theses
dc.identifierPalomaresVelosa_colostate_0053N_12763.pdf
dc.identifier.urihttp://hdl.handle.net/10217/88550
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.subjectBayesian
dc.subjectdiagnostic test
dc.subjectsensitivity
dc.subjectspecificity
dc.subjectCryptosporidium
dc.subjectGiardia
dc.titleAcurracy assessment of four diagnostic tests for the detection of Giardia and Cryptosporidium in the absence of gold standard: a Bayesian approach
dc.typeText
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineClinical Sciences
thesis.degree.grantorColorado State University
thesis.degree.levelMasters
thesis.degree.nameMaster of Science (M.S.)

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