T-score
Also called: T score
What it means
A T-score shows how your bone density compares to a healthy young adult, measured in standard deviations, and it's used to classify bone density as normal, osteopenia, or osteoporosis.
Knowing your T-score, and what it does and doesn't mean, helps you ask better questions about your own fracture risk and bone health trends.
A T-score is a number from a DEXA scan that tells you how your bone mineral density compares to a healthy young adult, measured in standard deviations. A T-score of -1.0 or above is considered normal, -1.0 to -2.5 is called osteopenia, and -2.5 or below is called osteoporosis. These cutoffs are useful conventions for research and treatment decisions, not sharp biological lines — nothing dramatic happens in your bone between a -2.4 and a -2.6.
Your scan report will usually list T-scores for the spine, femoral neck, and total hip separately, and they often don't match. That's because the spine contains more fast-turnover trabecular bone while the hip is more cortical. Diagnosis is conventionally based on your lowest valid site. Things like spinal arthritis, calcified arteries, and old compression fractures can add extra mineral signal and make a spine reading falsely look better, which is why the hip result matters too.
A T-score is also only part of the picture. Your actual 10-year fracture probability, calculated through tools like FRAX, matters more clinically, since someone with milder osteopenia but other risk factors can carry higher real risk than someone with a lower T-score. It's worth asking your physician for your T-score at each site, your Z-score if you're premenopausal or a man under 50, and your absolute fracture risk together, since bone health is best understood as a trend over time rather than a single snapshot.
How sure is this?
Graded Established Science: Supported by broad scientific consensus and decades of research. Read each study with its grade in mind. One study is a piece of the picture, not the whole of it.
Where the Academy teaches it
This page is the short version. The lessons teach it in full, with the context around it and a quiz to lock it in.
Questions people ask about this
A T-score compares your bone density to that of a healthy young adult, measured in standard deviations: -1.0 and above is normal, -1.0 to -2.5 is osteopenia, and -2.5 or below is osteoporosis. But it's just one snapshot of density — it doesn't capture bone quality, your fall risk, or your overall fracture probability, so it's worth tracking several other things alongside it and discussing them with your physician.
Read the full answer →Osteopenia and osteoporosis are both based on your DEXA T-score, just at different points on the same scale. A T-score between -1.0 and -2.5 is called osteopenia (lower-than-average bone mineral density), while -2.5 or below is called osteoporosis (more significant bone loss). They're not two different diseases — they're a continuum, and the cut-off points are statistical conventions used for research and reimbursement, not a biological cliff where something suddenly changes in your skeleton.
Read the full answer →A DEXA scan uses a low dose of X-ray to measure bone mineral density at the hip and spine, and it's the long-established standard that generates your T-score. A REMS scan uses ultrasound instead of radiation to assess the same areas, comparing the echo signal to reference models to produce its own T-score (not directly interchangeable with a DEXA T-score) plus a separate "fragility score" reflecting tissue quality. REMS is newer, has less long-term data, and is best used alongside DEXA rather than replacing it, especially if you already have a DEXA history.
Read the full answer →For most people, the honest answer is every 1 to 2 years. DEXA machines have a built-in measurement error, and most facilities can't reliably detect a real change in bone density sooner than that — a small shift of 1-2% on your scan often just reflects machine noise, not actual bone loss or gain. Your physician can tell you the right interval for your specific situation.
Read the full answer →A T-score compares your bone density to that of a healthy young adult at peak bone mass, and it's the number used to apply the standard categories of normal, osteopenia, or osteoporosis. A Z-score instead compares you to people of your own age and sex, which makes it the more appropriate number for anyone premenopausal, for men under 50, and for children, since a T-score can be misleading in those groups.
Read the full answer →Related words
A Z-score compares your bone density to other people your own age and sex, which matters most for younger adults,…
A DEXA scan is a low-radiation X-ray test that measures how much mineral is in your hip and spine bones, giving you…
Osteopenia means your bone density, as measured by a DEXA scan, is lower than average but not as low as osteoporosis…
Osteoporosis is a condition where bone breakdown outpaces bone building, causing bones to become thinner, more…
FRAX is a free online tool that calculates your 10-year probability of having a major osteoporotic fracture or hip…
Bone mineral density (BMD) measures how much mineral is packed into your bones, usually estimated with a DEXA scan,…
Education only, not medical advice. Decisions about tests, medications and treatment belong with your own doctor. OsteoStrong does not diagnose, treat or cure any disease.
