Qualification versus validation of biomarkers

The phases of research used to evaluate new drugs provide a useful reference point for determining the studies that need to be conducted to evaluate new biomarkers. However, biomarkers do not have a single pathway for changing health outcomes and may be used for a variety of purposes, such as improving diagnostic criteria, improving prognosis, improving the monitoring of disease or as a measurement of health outcomes. The impact on health outcomes is also less direct and is dependent on the sequence of actions taken as a consequence of the test results. The different purposes of biomarkers and the less direct effect on health outcomes require different study designs to those used for the evaluation of pharmaceutical products and a more careful interpretation of results. Greater collaboration between researchers designing laboratory-based qualification studies and researchers designing clinical validation studies could achieve a process of evaluation for biomarkers that is both reliable and efficient.