title: [Critical reading of articles about diagnostic tests (part II): Analyzing results].
abstract: A new diagnostic test needs to be validated through comparison with a reference standard in an appropriate spectrum of patients. Diagnostic tests are not perfectly accurate; on the contrary, there can be false-positive and false-negative findings. A good diagnostic test is that which provides an acceptable proportion of positive results when a determinate condition is present in patients and an acceptable proportion of negative results when it is absent. The best measure of the usefulness of a diagnostic test is the likelihood ratio, which informs us to what degree a particular result is more likely in a person in whom a condition is present than in a person in whom the condition is absent. The present article discusses the fundamental statistical concepts necessary to interpret the results section of an article about a diagnostic test; however, the approach is clearly oriented toward clinical practice, with emphasis on concepts rather than mathematics.
authors.affiliation: Centro de Salud Loreto-Puntales, Distrito Sanitario Bahía de Cádiz-La Janda, Cádiz, España. Electronic address: morrogui@gmail.com.
authors.forename: G
authors.initials: G
authors.lastname: Moratalla Rodríguez
mesh_terms: D003627:Data Interpretation, Statistical; D003955:Diagnostic Tests, Routine / Q000706:statistics & numerical data; D012372:ROC Curve; D011932:Reading; D015203:Reproducibility of Results; D013850:Thinking
keywords: Diagnosis; Diagnostic imaging; Diagnostic techniques and procedures; Diagnóstico; Diagnóstico por Imagen; Predictive value of tests; Sensibilidad y especificidad; Sensitivity and specificity; Técnicas y procedimientos diagnósticos; Valor predictivo de las pruebas