Assessing strength of evidence in diagnostic tests

Clinical encounters between clinicians and patients begin with an attempt at diagnosis, a foundational element in determining a patient's ultimate outcome. Diagnosis that is expedient and accurate will result in a treatment that is expedient, appropriate, and cost-effective. In essence, evidence-based diagnosis is as vital as evidence-based intervention and treatment. If surgeons are committed to making expedient and accurate diagnoses, they must strive to apply diagnostic tests not just on the basis of ease, novelty, or availability but for the soundness of evidence behind them. In the scopes of both aesthetic and reconstructive surgery, advocating evidence-driven diagnostic test use is relevant. A pertinent example of how this relates to plastic surgery is the U.S. Food and Drug Administration recommendation to screen asymptomatic women with silicone breast implants with magnetic resonance imaging. For an important recommendation such as this that has tremendous cost implications to patients, sound study design and rigorous evaluation of the accuracy of magnetic resonance imaging as a screening tool has important health policy implications. The authors demonstrate how to determine the accuracy of diagnostic tests and, more importantly, illustrate the essential qualities of any study to establish the accuracy of a diagnostic test.