Understanding diagnostic tests. Part 3.

1. Methods in Epidemiologic, Clinical, and Operations Research–MECOR–program, American Thoracic Society/Asociación Latinoamericana del Tórax, Montevideo, Uruguay. 2. Divisão de Pneumologia, Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo (SP) Brasil. 3. Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles (CA) USA. a. http://orcid.org/0000-0001-6548-1384; b. http://orcid.org/0000-0001-5742-2157 In the previous articles from this series(1,2) we discussed important characteristics used in order to evaluate diagnostic tests: sensitivity, specificity, positive predictive value, and negative predictive value. In this final part, we discuss positive likelihood ratio (LR+), negative likelihood ratio (LR−), and ROC curves.