The problem
A lab report is a photograph of a moving body.
Clinical medicine reads biomarkers one at a time, at one moment, against a fixed normal range. The physiology underneath is continuous, interacting and in motion.
Cut-offs hide the shape of risk
A value is "normal" or "high". Yet mortality risk rises smoothly across the range, often well inside it, and for many markers it is U-shaped: too low is dangerous as well as too high. Of the 238 biomarkers in the PFL catalogue, 63 have U-shaped hazard curves.
Two people flagged "normal" can sit on very different ground. One can be on a flat plateau, the other at the lip of a slope.
Markers are read alone
The risk carried by blood pressure depends on kidney function. The risk carried by inflammation depends on albumin. In national data the combined effect of these pairs is measurably different from the sum of their parts.
A report that lists them in separate rows cannot show that.
A snapshot has no direction
A grip strength of 31 kg means one thing in someone who has held it for a decade and another in someone who lost 10 kg in the last few years. In the Health and Retirement Study, men's average grip falls from 41 kg twelve years before death to 31 kg in the last two.
Direction and speed carry information that a single value cannot.
So prevention arrives late
When risk is only recognised once a threshold is crossed, the decade of drift before it goes unmeasured. That decade is where intervention is cheapest and most effective.