How Often Should You Have a DEXA Scan After 50?

The short answer: it depends on your starting T-score and your risk profile. The longer answer matters because re-scanning too often produces noise that gets misread as progress or decline; re-scanning too rarely misses meaningful changes you could have addressed.

The typical re-scan intervals

• Normal T-score (≥ -1.0) and low risk profile: every 5-10 years. Most postmenopausal women in this category do not need annual scans.
• Osteopenia (T-score -1.0 to -2.5), stable: every 2-3 years. Long enough to detect a real trajectory change.
• Osteoporosis (T-score ≤ -2.5), no medication: every 1-2 years.
• On medication (bisphosphonate, denosumab, romosozumab): every 1-2 years to monitor response.
• Glucocorticoid use or other secondary risk: every 1 year while the risk factor is active.

Why not annually for everyone

The measurement error of a DEXA scan is roughly 1-1.5% at typical clinical sites. The least significant change (LSC) — the change you need to see to be confident it is real and not noise — is usually 3-5%. Bone density changes slowly enough that two scans 6-12 months apart often cannot distinguish signal from measurement noise. Scanning too often produces results that get over-interpreted in both directions.

What to ask your radiology center

Ask for the facility’s least significant change (LSC) number for each site (lumbar spine, total hip, femoral neck). This is the threshold below which a change is statistically meaningless. Many patients are told “your spine T-score went from -2.1 to -2.0, you are improving” when the change is well within LSC and means nothing.

The other measurements that come with a DEXA

Modern DEXA reports often include:

• Trabecular Bone Score (TBS) — a proxy for bone microarchitecture that captures something T-score does not. Ask whether your facility provides it.
• Vertebral Fracture Assessment (VFA) — a lateral image of your spine to look for silent vertebral fractures. Worth requesting if you are over 70, have lost height, or are on chronic steroids.
• Body composition — some facilities include lean and fat mass, useful for muscle-tracking alongside bone density.

FAQ

Will insurance cover DEXA every year?

In the US, Medicare covers DEXA every 24 months for screening; more frequently if medically indicated. Private insurance varies. Check before scheduling.

Can I use the same DEXA machine each time?

Strongly recommended. Comparing scans from different machines introduces calibration differences that can look like meaningful changes when they are not.

What about portable heel ultrasound?

Useful as a screening tool to flag who needs a real DEXA. Not accurate enough for diagnosis or monitoring.

Related reading: Bones After 50 home