Table 2. Requirements for a Marker-Based Test to Reach
Level IB Evidence of Clinical Utility on the Basis of
Prospective-Retrospective Studies
Requirements
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 the
evaluation of a completely defined marker-based test.
4. The results from archived specimens should be validated by using specimens from one or
more similar, but separate studies.
NOTE. Adapted from Simon et al. J Natl Cancer Inst. 2009;101:1446-1452.
