Article

Grading quality of evidence and strength of recommendations for diagnostic tests and strategies.

Department of Epidemiology, Italian National Cancer Institute Regina Elena, 00144 Rome, Italy.
BMJ (online) (Impact Factor: 16.38). 06/2008; 336(7653):1106-10. DOI: 10.1136/bmj.39500.677199.AE
Source: PubMed

ABSTRACT The GRADE system can be used to grade the quality of evidence and strength of recommendations for diagnostic tests or strategies. This article explains how patient-important outcomes are taken into account in this processSummary pointsAs for other interventions, the GRADE approach to grading the quality of evidence and strength of recommendations for diagnostic tests or strategies provides a comprehensive and transparent approach for developing recommendationsCross sectional or cohort studies can provide high quality evidence of test accuracyHowever, test accuracy is a surrogate for patient-important outcomes, so such studies often provide low quality evidence for recommendations about diagnostic tests, even when the studies do not have serious limitationsInferring from data on accuracy that a diagnostic test or strategy improves patient-important outcomes will require the availability of effective treatment, reduction of test related adverse effects or anxiety, or improvement of patients’ wellbeing from prognostic informationJudgments are thus needed to assess the directness of test results in relation to consequences of diagnostic recommendations that are important to patientsIn this fourth article of the five part series, we describe how guideline developers are using GRADE to rate the quality of evidence and move from evidence to a recommendation for diagnostic tests and strategies. Although recommendations on diagnostic testing share the fundamental logic of recommendations on treatment, they present unique challenges. We will describe why guideline panels should be cautious when they use evidence of the accuracy of tests (“test accuracy”) as the basis for recommendations and why evidence of test accuracy often provides low quality evidence for making recommendations.Testing makes a variety of contributions to patient careClinicians use tests that are usually referred to as “diagnostic”—including signs and symptoms, imaging, biochemistry, pathology, and psychological testing—for various purposes.1 These purposes include identifying physiological derangements, establishing prognosis, monitoring illness and response to treatment, and diagnosis. This article …

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