Features for a bioscale that enable its role as a surrogate for a clinical end point beyond the NIH definition of a biomarker

No.	Properties of a Bioscale	Implications
1	Image-derived map of the disease site	More sensitivity to earlier disease than diluted remote biomarkers
2	Spatially resolved quantitative parameter	Precise and accurate measurement
3	Small biologic variance in the healthy population	Sensitivity to early disease
4	Continuously and monotonically varying with disease progression	Sensitivity to disease progression or response to treatment
5	Intrinsically related to the disease mechanism	Highly conserved metabolic parameter, essential for use as a surrogate of a clinical end point

Note:—NIH indicates National Institutes of Health.