Testes de rastreamento x testes de diagnóstico: atualidades no contexto da atuação fonoaudiológica*** Screening versus diagnostic tests: an update in the speech, language and hearing pathology practice

Background: evaluation instruments, properties, selection indicators, application and validation of screening and diagnostic tests. Aim: to present some concepts concerning screening and diagnostic tests and their application according to a specific purpose. To present a few practical examples of the application of these instruments related to human communication, as well as to present validation criteria of tests in the population and criteria used for the rational selection of screening or diagnostic instruments in health programs and health services based on epidemiological concepts indexed in Scielo, Lilacs or Medline up to January 2007. Conclusion: diagnostic instruments differ from screening instruments in their objectives and eligibility criteria. Sensibility and specificity are two important indicators to be considered when choosing an instrument for screening or diagnosis. Reproducibility, time required to complete the evaluation and previous preparation of patients, if needed, are also indicators to be considered when choosing an instrument. Publication and information exchange regarding the properties of evaluation instruments, used for diagnosis or screening, related to the Speech, Language and Hearing Sciences must be systematically stimulated. Besides that, improving the knowledge about methodologies and evaluation instruments under different perspectives contribute to the better use of human and financial resources. Furthermore, the elaboration of studies that promote the correct validation of screening and diagnostic instruments used in human communication disorders contributes to the increase in knowledge in the field of Speech, Language and Hearing Sciences and, indirectly, to the acknowledgement of this science, based on technical-scientific evidence, in health promotion.