T-score
Bone density expressed in standard deviations relative to young-adult peak bone mass. The headline DXA clinical number used in WHO osteoporosis classification:
- T ≥ −1.0 — normal.
- T −1.0 to −2.5 — osteopenia (low bone mass).
- T ≤ −2.5 — osteoporosis.
- T ≤ −2.5 with fragility fracture — severe (established) osteoporosis.
Used clinically alongside Z-score (age-matched comparison) and FRAX 10-year fracture-risk modeling.
Why it matters to buyers: Primary DXA clinical output — reported on every bone-density scan and used directly for treatment decisions (bisphosphonates, denosumab, romosozumab).
Why it matters to engineers: Manufacturer-specific calibration — T-scores across GE Lunar vs Hologic are not perfectly interchangeable, which is why clinical practice locks patients to a single platform across decades for serial-comparison continuity. Daily phantom QC on the same hardware verifies precision; ISCD-aligned guidelines define how to handle a vendor switch.