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Computational and Mathematical Methods in Medicine
Volume 2012, Article ID 487502, 12 pages
Research Article

A General Latent Class Model for Performance Evaluation of Diagnostic Tests in the Absence of a Gold Standard: An Application to Chagas Disease

1Department of Education and Nursing Community Health, Federal University of Triângulo Mineiro, 38025-180 Uberaba, MG, Brazil
2Department of Applied Mathematics and Statistics, ICMC, University of São Paulo, 13560-970 São Carlos, SP, Brazil
3Research Group for Blood Transfusion Security, Federal University of Triângulo Mineiro, 38025-180 Uberaba, MG, Brazil
4Postgraduate Student in Clinical Pathology, Federal University of Triângulo Mineiro, 38025-180 Uberaba, MG, Brazil
5Discipline of Hematology, Federal University of Triângulo Mineiro, 38025-180 Uberaba, MG, Brazil

Received 23 March 2012; Revised 3 May 2012; Accepted 25 May 2012

Academic Editor: Guang Wu

Copyright © 2012 Gilberto de Araujo Pereira et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We propose a new general Bayesian latent class model for evaluation of the performance of multiple diagnostic tests in situations in which no gold standard test exists based on a computationally intensive approach. The modeling represents an interesting and suitable alternative to models with complex structures that involve the general case of several conditionally independent diagnostic tests, covariates, and strata with different disease prevalences. The technique of stratifying the population according to different disease prevalence rates does not add further marked complexity to the modeling, but it makes the model more flexible and interpretable. To illustrate the general model proposed, we evaluate the performance of six diagnostic screening tests for Chagas disease considering some epidemiological variables. Serology at the time of donation (negative, positive, inconclusive) was considered as a factor of stratification in the model. The general model with stratification of the population performed better in comparison with its concurrents without stratification. The group formed by the testing laboratory Biomanguinhos FIOCRUZ-kit (c-ELISA and rec-ELISA) is the best option in the confirmation process by presenting false-negative rate of 0.0002% from the serial scheme. We are 100% sure that the donor is healthy when these two tests have negative results and he is chagasic when they have positive results.