Table 1.

Requirements for a Marker-Based Test to Reach Level IB Evidence of Clinical Utility Based on Prospective-Retrospective Studies

1. Adequate amounts of archived specimen must be available from enough patients from a prospective trial (which for predictive factors should generally be a randomized design) for analyses to have adequate statistical power and for the patients included in the evaluation to be clearly representative of the patients in the trial. 2. The marker-based test should be analytically and preanalytically validated for use with archived specimens. 3. The plan for marker evaluation should be completely specified in writing before the performance of marker assays on archived specimens and should be focused on evaluation of a single completely defined marker-based test. 4. The results from archived specimens should be validated using specimens from one or more similar, but separate, studies.

NOTE. Guidelines adapted.²²