This is a Portuguese translation of the ninth in a series of 36 blogs explaining 36 Key Concepts we need to be able to understand to think critically about treatment claims. With thanks to Ney Duarte Neto and Cochrane Brazil for the translation.
This blog explains that people often assume that early detection of disease leads to better outcomes. However screening tests can be inaccurate (e.g. misclassifying people who do not have disease as having disease). Screening can also cause harm by labelling people as being sick when they are not and because of side effects of the tests and treatments.