Table 1.

BEST biomarkers proposed by the FDA/NIH Working Group.^a

Biomarker type	Biomarker definition
Susceptibility/risk biomarker	A biomarker that indicates the potential for developing a disease or medical condition in an individual who does not currently have clinically apparent disease or the medical condition [see Torres et al.4]
Predictive biomarker	A biomarker used to identify individuals who are more likely than similar individuals without the biomarker to experience a favourable or unfavourable effect from exposure to a medical product or an environmental agent
Diagnostic biomarker	A biomarker used to detect or confirm presence of a disease or condition of interest or to identify individuals with a subtype of the disease
Monitoring biomarker	A biomarker measured serially for assessing status of a disease or medical condition or for evidence of exposure to [or effect of] a medical product or an environmental agent
Pharmacodynamic/response biomarker	A biomarker used to show that a biological response has occurred in an individual who has been exposed to a medical product or an environmental agent
Safety biomarker	A biomarker measured before or after an exposure to a medical product or an environmental agent to indicate the likelihood, presence, or extent of toxicity as an adverse effect
Prognostic biomarker	A biomarker used to identify likelihood of a clinical event, disease recurrence, or progression in patients who have the disease or medical condition of interest
Reasonably likely surrogate endpoint	An endpoint supported by strong mechanistic and/or epidemiological rationale such that an effect on the surrogate endpoint is expected to be correlated with an endpoint intended to assess clinical benefit in clinical trials, but without sufficient clinical data to show that it is a validated surrogate endpoint

^aFDA-NIH Biomarker Working Group. BEST [Biomarkers, EndpointS, and other Tools] Resource [Internet]. Silver Spring [MD]: Food and Drug Administration [US]; 2016. Bethesda MD: co-published by National Institutes of Health [US]; 2016.⁵