Most patients leave a DEXA scan with a printout they can't read. The report lists numbers like −1.8 or −2.6 alongside terms like "osteopenia" or "TBS," and the appointment with the referring doctor is still two weeks away. This page breaks down exactly what those numbers mean, how Canadian doctors use them to make treatment decisions, and what to ask at your follow-up.
Your DEXA report will include one or both of these scores, and they answer completely different questions. Confusing them — or using the wrong one — leads to misinterpretation.
T-score compares your bone density to the average peak bone mass of a healthy young adult (25–30 years old). It's expressed in standard deviations below or above that young-adult average. A T-score of −1.8 means your bone density is 1.8 standard deviations below peak. This is the score used for diagnosing osteopenia and osteoporosis in post-menopausal women and in men aged 50 and older.
Z-score compares your bone density to the average for someone your own age and sex. A Z-score of −1.8 means your bones are significantly lower density than your peers of the same age — which suggests something beyond normal aging is happening. Z-scores are used for pre-menopausal women, men under 50, and children.
If you're 62 years old and post-menopausal, your T-score is the clinically relevant number. If you're 38 and your doctor ordered a DEXA due to long-term prednisone use, your Z-score is what matters. A Z-score below −2.0 prompts investigation for secondary causes — see secondary osteoporosis causes for what to look for.
The World Health Organization (WHO) established these cutoffs in 1994 based on hip fracture data in post-menopausal white women. They've been adopted globally, including in Canadian clinical practice, though they have limitations — particularly for men and non-white populations.
| T-Score Range | WHO Category | What It Means in Practice |
|---|---|---|
| −1.0 or above | Normal | Bone density within normal range for a young adult |
| −1.0 to −2.5 | Osteopenia (low bone mass) | Lower than normal; not disease but increased fracture risk |
| −2.5 or below | Osteoporosis | Meets diagnostic threshold; treatment discussion warranted |
| −2.5 or below + fragility fracture | Severe osteoporosis | Established osteoporosis; treatment strongly indicated |
Two numbers are reported: your hip T-score and your spine (lumbar) T-score. The worse of the two is used for diagnosis. These often differ — it's common to have a normal spine score but a low hip score, or vice versa. The femoral neck T-score is considered the gold standard for fracture risk prediction.
A note on "osteopenia": this label causes significant anxiety. It does not mean you have bone disease or will definitely develop osteoporosis. It means bone density is below the young-adult average, which is true of about half of Canadian women over 50. What matters clinically is not the category label but your individual fracture risk — which is where FRAX comes in.
TBS (Trabecular Bone Score) is a texture analysis of the lumbar spine DEXA image that provides information about bone microarchitecture — essentially, the internal structure of the bone, not just its density. A bone can have a decent density (T-score) but poor microarchitecture, which increases fracture risk. TBS captures some of that.
TBS values are interpreted as follows: above 1.350 is normal, 1.200–1.350 is partially degraded, and below 1.200 is degraded. A degraded TBS increases fracture risk independent of T-score, and can shift a patient's FRAX score upward.
Here's why many patients don't get TBS on their report: it requires a software license (TBS iNsight, developed by Medimaps Group) that not every DEXA facility has purchased. The scan hardware is the same — a standard Hologic or GE/Lunar DXA machine — but the TBS analysis runs as a software add-on. Many community DEXA facilities in Canada, particularly outside major urban centres, don't have this software.
This is a common source of frustration on forums like r/osteoporosis, where patients compare reports and notice some have TBS values and others don't. The absence of TBS does not mean your report is incomplete — it means your facility doesn't have the analysis software. If TBS is clinically important for your case (particularly with Type 2 diabetes, obesity, or glucocorticoid use, where bone quality diverges from density), ask your doctor whether referral to a centre with TBS capability makes sense.
The FRAX tool, developed at the University of Sheffield, calculates your 10-year probability of a major osteoporotic fracture (spine, hip, wrist, or shoulder) and specifically of a hip fracture. It combines your T-score with clinical risk factors — age, sex, weight, prior fracture, parental hip fracture, smoking status, alcohol use, glucocorticoid use, rheumatoid arthritis, and secondary osteoporosis.
FRAX can be run with or without BMD. Without BMD, it's less precise but still useful for screening. With BMD, it's the most accurate fracture risk prediction tool available in clinical practice. The Canadian version is available free at frax.shef.ac.uk — select "Canada" as the country.
Osteoporosis Canada's 2023 clinical practice guidelines use FRAX to guide treatment decisions. The thresholds vary slightly by province, but the national framework is:
A T-score alone in the osteopenia range does not automatically mean you need medication. If your FRAX puts you at low risk, observation and lifestyle changes may be entirely appropriate. Conversely, a T-score only mildly in the osteoporosis range can push a patient to high-risk treatment territory when FRAX risk factors are added. This is why your doctor should be calculating FRAX, not just handing you the T-score.
FRAX uses femoral neck T-score only — it doesn't incorporate the spine score. It underestimates risk in patients who have had multiple vertebral fractures. It also doesn't fully account for fall risk, which is a major independent predictor of hip fracture. Ask your doctor if your FRAX needs a "fall risk adjustment" — some Canadian guidelines acknowledge this gap.
DEXA machines are made primarily by two manufacturers: Hologic and GE/Lunar. T-scores from these machines are not always directly comparable — there can be small systematic differences. If you switch facilities for your repeat scan, make sure the same machine brand is used when possible, or note that cross-calibration may affect interpretation.
The scan sites also matter. The standard clinical DEXA measures the lumbar spine (L1–L4) and the proximal femur (femoral neck and total hip). Some reports also include the forearm (1/3 radius), which is primarily used when hip or spine results are unreliable (e.g., severe arthritis, bilateral hip replacements). The forearm site is not used for diagnosis unless the other sites are unavailable.
DEXA coverage varies by province. The broad rules are consistent but the specifics differ:
| Province | Coverage Criteria (Summary) |
|---|---|
| British Columbia | Women 65+; men 70+; 50+ with risk factors (prior fragility fracture, glucocorticoid use, BMI <20, etc.); MSP covers initial + follow-up scans |
| Alberta | Women 65+; men 70+; any age post-fragility-fracture; 50+ on glucocorticoids ≥3 months; follow-up covered at 1–2 year intervals on treatment |
| Ontario | OHIP covers for women 65+, men 70+, post-fragility-fracture, high-risk groups (glucocorticoids, specific conditions) |
| Saskatchewan/Manitoba | Similar criteria; 65+ routine, or 50+ with specific risk factors; rural access more limited |
| Quebec | RAMQ covers women 60+, men 65+; specific risk factor pathways for younger ages |
If you're under 65 and your doctor wants to order a DEXA, coverage depends on having a documented risk factor. This is not just bureaucracy — it's an opportunity: if you have even one significant risk factor, make sure your doctor documents it on the requisition. An uncovered scan at a private imaging clinic typically costs $75–$150 in Canada, which is affordable, but covered is better.
In major urban centres — Toronto, Vancouver, Calgary, Edmonton, Montreal — wait times for DEXA are generally 1–4 weeks from referral. Most hospital-based and private imaging centres keep reasonable throughput because the scan itself takes only 10–20 minutes and doesn't require preparation.
In rural and remote areas of BC, Alberta, and Saskatchewan, wait times of 2–3 months are common. Patients in smaller communities may need to travel to the nearest regional centre. If you're in a rural area and have significant risk factors, ask your GP to flag urgency on the requisition — this sometimes moves the timeline.
Repeat scans during treatment or a bisphosphonate drug holiday are typically timed at 1–2 year intervals. Going sooner rarely changes management and wastes the coverage slot.
Your T-score is a data point, not a verdict. These questions will get you the context you actually need:
If you've already had a fragility fracture (a break from a fall from standing height or less, or a vertebral fracture from minimal force), treatment is almost always indicated regardless of the T-score. A post-fracture bone density test confirms severity and provides the baseline for monitoring treatment response. See the fracture risk calculator page for more on FRAX inputs.
Your DEXA report will include a BMD value in grams per square centimetre (g/cm²), the T-score, and often a percentile or graph showing where you fall compared to reference populations. Some reports include both WHO category labels and Osteoporosis Canada risk categories — these sometimes differ slightly because the Canadian framework adjusts for age-related considerations.
If the report says "vertebral fracture assessment" (VFA), your scan included a lateral spine image to check for compression fractures you might not have known about. Silent vertebral fractures are common — about 25% of women over 70 have had one without obvious symptoms. A positive VFA finding automatically moves you into the severe osteoporosis category for treatment purposes.