This article is the fourth translation of a GRADE series published in the BMJ, which graded the quality of evidence and strength of recommendations for diagnostic tests or strategies, as a comprehensive and transparent approach for developing re-commendations. Randomized trials for diagnostic approaches represent the ideal study design for intervention studies. On the other hand, cross-sectional or cohort studies with a direct comparison of the test results with an appropriate reference standard can provide high-quality evidence. The guideline panel must be reminded that the test accuracy is a surrogate for patient-important outcomes, so such studies often provide a low quality of evidence for recommendations regarding diagnostic tests, even when the studies do not have serious limitations. Diagnostic accuracy studies showing that a diagnostic test or strategy improves important patient outcomes will require the availability of effective treatment, reduction of test- related adverse effects or anxiety, or improvement of the patients’ well-being from prognostic information. Therefore, it is important to assess the directness of the test results regarding the consequences of diagnostic recommendations that are im-portant to patients.