DEXA Scan in Canada: Your Bone Density Test Explained

A DEXA scan is the gold standard for measuring bone mineral density in Canada. If you've been referred for one — or are wondering whether you should be — here's exactly what to expect, what your results mean, and how to navigate the system.

What Is a DEXA Scan?

DEXA stands for Dual-Energy X-ray Absorptiometry. It uses two low-dose X-ray beams at different energy levels to measure the density of your bones at specific sites — typically the lumbar spine (lower back vertebrae), the hip (femoral neck and total hip), and sometimes the forearm. The scan measures Bone Mineral Density (BMD), expressed in grams per square centimetre (g/cm²).

The test is quick (typically 10–20 minutes), painless, and requires no injections or special preparation. Radiation exposure is minimal — roughly one-tenth the dose of a chest X-ray, similar to a few hours of normal background radiation. You remain fully clothed (metal-free) for most DEXA measurements.

What DEXA Measures and Doesn't Measure

DEXA measures mineral density — the amount of calcium and other minerals packed into a given area of bone. It's the most widely validated measure for predicting fracture risk. What it doesn't fully capture is bone quality: the microarchitectural strength of trabecular bone (the spongy inner network) and bone turnover rates. This is why a DEXA result is best interpreted alongside your full clinical picture, not in isolation.

DEXA also doesn't directly measure bone size, and smaller-framed people naturally have lower BMD scores than larger-framed people — which is part of why sex and age-matched comparison groups are used for interpretation.

T-Score vs Z-Score: What They Mean

Your DEXA report will include two scores. Understanding both is important.

T-Score

Your T-score compares your bone density to the peak bone mass of a healthy young adult (the reference standard is a 30-year-old of the same sex). It's expressed as standard deviations above or below that average:

T-Score	WHO Classification
−1.0 and above	Normal bone density
−1.0 to −2.5	Osteopenia (low bone mass)
−2.5 and below	Osteoporosis
−2.5 and below with a fragility fracture	Severe osteoporosis

T-scores are used for post-menopausal women and men over 50. A T-score of −2.5 means your bone density is 2.5 standard deviations below peak young adult bone mass. Each standard deviation below normal roughly doubles fracture risk.

Z-Score

Your Z-score compares your bone density to the average for people of your age, sex, and body size. A Z-score below −2.0 suggests your bone density is lower than expected for your age — which prompts investigation for secondary causes (medical conditions or medications causing bone loss). Z-scores are used in premenopausal women, men under 50, and children, because T-scores aren't appropriate for these groups.

Which score matters more? For treatment decisions in older adults, T-score is the primary clinical tool. Z-score helps identify whether bone loss is age-related (expected) or from another cause that needs treatment. Both appear on your report — make sure your doctor explains both.

Who Should Get a Bone Density Test in Canada

Osteoporosis Canada recommends a DEXA scan for:

All women age 65 and older
All men age 70 and older
Post-menopausal women under 65 with risk factors (family history of osteoporosis or hip fracture, prior fracture after age 40, current smoking, low body weight, excessive alcohol consumption)
Men and women aged 50–64 who have had a fragility fracture (a fracture from a fall from standing height or less)
Anyone starting or on long-term oral corticosteroids (prednisone) — even short-term high-dose steroids accelerate bone loss
Anyone with conditions known to cause bone loss: rheumatoid arthritis, inflammatory bowel disease, celiac disease, hyperparathyroidism, hyperthyroidism, chronic kidney disease
Anyone on medications associated with bone loss: aromatase inhibitors (breast cancer treatment), androgen deprivation therapy (prostate cancer), anticonvulsants, some diabetes medications

Provincial Coverage in Canada

DEXA scan coverage varies by province. In most provinces, DEXA is covered under provincial health insurance when ordered by a physician for an eligible indication (the criteria listed above). However, there are important caveats:

Ontario (OHIP) — Covered for women 65+, men 65+, anyone with a fragility fracture, anyone on long-term steroids, and certain other high-risk situations. Not covered for general screening of 50-year-olds without specific risk factors.
British Columbia (BC MSP) — Similar eligibility. Covered for post-menopausal women, men over 50 with risk factors, and confirmed high-risk groups. Your physician must order it with an appropriate indication.
Alberta (AHCIP) — Covered for eligible indications ordered by a physician. Generally follows Osteoporosis Canada guidelines.
Quebec (RAMQ) — Covered for qualifying indications. Quebec has relatively strict criteria; discuss eligibility with your doctor.
Other provinces — Generally covered when medically indicated. Check with your provincial health plan or ask your physician.

If you don't meet the criteria for covered testing but want a baseline scan, private DEXA scans are available at some diagnostic imaging clinics for approximately $80–150 CAD out of pocket. Ask your doctor for a referral even to a private clinic — the scan must be read by a radiologist.

How to Prepare for Your DEXA Scan

No calcium supplements 24 hours before — Calcium supplements can coat the bones and interfere with the scan reading. Stop them the day before.
Wear comfortable, metal-free clothing — No zippers, underwire bras, or belt buckles. You'll stay dressed for the scan (unlike an MRI).
No recent contrast scans — If you've recently had a CT scan with contrast dye or a nuclear medicine scan, wait at least a week. Contrast materials can interfere with DEXA results.
Inform the technician of any implants or hardware — Spinal fusion hardware, hip replacements, or other metal implants affect the interpretation of scans at those sites.
Consistent timing for follow-up scans — For meaningful comparison between scans (done every 1–3 years typically), try to use the same machine at the same facility. Different machines give slightly different readings.

Understanding Your Results and Next Steps

After your DEXA, you'll receive a report with T-scores and Z-scores at each measured site (spine and hip). The "worst" score determines your overall classification. Your doctor will typically use this alongside the FRAX tool — a validated risk calculator that estimates your 10-year probability of a major osteoporotic fracture based on bone density, age, sex, weight, and clinical risk factors.

A diagnosis of osteopenia doesn't automatically mean medication — many people with osteopenia manage well with lifestyle changes (exercise, nutrition, supplements). Osteoporosis (T-score below −2.5) typically prompts a conversation about prescription medication in addition to lifestyle. The most commonly prescribed drugs in Canada are bisphosphonates (alendronate/Fosamax, risedronate/Actonel) — weekly oral pills that slow bone resorption. See our full osteoporosis guide for a detailed breakdown of treatment options.

How Often Should You Be Retested?

Repeat DEXA frequency depends on your results and risk factors:

Normal bone density — Retest every 3–5 years (or as directed by your physician)
Osteopenia — Retest every 1–3 years depending on your T-score and risk factors
Osteoporosis on treatment — Retest every 1–2 years to assess treatment response
New corticosteroid use — Retest within 6–12 months of starting high-dose steroids

Medical Disclaimer: This article is for educational purposes only. DEXA scan interpretation should always be done by a physician in the context of your full medical history. Diagnostic and treatment decisions should be made with your healthcare provider.