Table 3. Phases of biomarker development

Adapted from reference 7.
1a. Initial preclinical discovery
    discovery biomarker on tissue or serum samples
1b. Confirmation of preclinical discovery
    Validate biomarker on same type of samples
        Promising direction identified and prioritized
2. Clinical assay development and validation
     set up clinical assay and test on existing samples
        clinical assay detects established disease
3. Retrospective longitudinal
     test biomarker in completed clinical trial
        detects disease early before it becomes clinically obvious
        “screen positive” rule is determined; evaluate sensitivity/specificity
4. Prospective screening
    Use biomarker to screen population
        extent and characteristics of disease detected by test
        false referral rate identified
5. Disease control
    impact of screening on reducing the burden of disease