The TRT Plus Overall Score: A Deterministic Piecewise-Linear Biomarker Composite for Men on Testosterone Therapy

Men on testosterone therapy are typically monitored with a broad blood panel, but results are reported marker by marker against general-population reference ranges that were not designed for this population. This note describes the Overall Score used in the TRT Plus app, a deterministic composite that summarises fifteen biomarkers — sixteen penalty terms, with systolic and diastolic blood pressure scored separately — as a single integer from 1 to 1,000. Each marker is classified into five colour classes (red-low, amber-low, green, amber-high, red-high) against a six-edge target band. A marker in its green band costs nothing. Outside it, the penalty rises linearly with distance through the amber zone and then the red zone, to separate low-side and high-side caps that act as the marker's weights. The score is 1,000 minus the sum of penalties, floored at 1, and is mapped to six labelled tiers. Several bands are coupled to other markers: the testosterone and haematocrit bands to a cardio-metabolic cascade, IGF-1 and SHBG to HbA1c, DHT to PSA, and estradiol to an androgen:estrogen ratio. We give the full scoring formula, band structure, couplings, tier cut-offs, substitution and missing-data rules, and limitations. Hormone target bands and marker weights are proprietary and withheld. The score has not been validated against health outcomes and is published as a methods description, not as clinical guidance.