§ 01 · DETECT
Establish the baseline.
The detection node is the one that answers the question, "What is actually true about this body right now?" Its practical form is the annual physical examination, done with the same physician when possible, generating the same core set of measurements each year. Blood pressure, resting heart rate, lipid panel, fasting glucose, hemoglobin A1c, complete blood count, thyroid panel, PSA or mammogram by age, colonoscopy by age. The results belong in a single document you can open from a phone. The document is the baseline. Every future measurement is read against it.