Bone density scans: who needs one, NHS vs private, and what your T-score means
Written by a UK GP · Updated
A bone density scan uses dual-energy X-ray absorptiometry (DEXA or DXA) to measure how much mineral is in your bones, usually at the hip and the lower spine. It is the standard test for diagnosing osteoporosis, a condition where bones become thinner and more likely to break.
Who is usually offered a bone density scan?
On the NHS, a scan isn't a routine screening test. Your GP first estimates your risk of a fracture over the next 10 years using a tool such as FRAX or QFracture, in line with NICE guidance. A DEXA scan may then be arranged when the result is close to the threshold for treatment, or when the scan result would change what happens next. People who are often assessed include:
- women aged 65 and over, and men aged 75 and over
- anyone who has broken a bone after a minor fall or bump (a “fragility fracture”)
- people taking steroid tablets long term, or some hormone-blocking treatments
- people with a parent who broke a hip, a low body weight, early menopause, or conditions that affect bone
- people who smoke or regularly drink more than 14 units of alcohol a week
This list is a summary, not a checklist. If any of it applies to you, the right first step is a conversation with your GP about your fracture risk.
NHS or private: what's the difference?
| NHS | Private | |
|---|---|---|
| How to get one | Referral from your GP or a specialist, based on your fracture risk | Usually self-referral, after screening questions |
| Cost | Free | Varies — see our price guide |
| Waiting time | Depends on local services | Often within days |
| What happens after | Your GP or specialist uses the result to plan treatment | You get a report; share it with your GP if it shows low bone density |
A private scan can be useful if you want an answer quickly, but a T-score on its own doesn't decide treatment. Your GP will still look at your overall fracture risk, so it helps to take a copy of the full report (not just a summary) to your appointment.
What does the T-score mean?
Your T-score compares your bone density with that of a healthy young adult of the same sex. It is measured in standard deviations: the lower the number, the thinner the bone. The World Health Organization categories are:
| T-score | Category |
|---|---|
| −1.0 or higher | Normal bone density |
| Between −1.0 and −2.5 | Low bone density (sometimes called osteopenia) |
| −2.5 or lower | Osteoporosis |
Your report may also show a Z-score, which compares you with people of your own age and sex. Z-scores are used instead of T-scores for children, younger adults and people before the menopause. A low Z-score can prompt a look for other causes of bone loss.
What happens during the scan?
You lie on your back on a padded table while a scanning arm passes over you. It doesn't enclose you and doesn't hurt. The scan usually takes 10 to 20 minutes and you can often stay in your clothes, as long as there's no metal near the areas being scanned. The X-ray dose is very low — typically less than a day of natural background radiation.
Tell the clinic before your scan if you:
- are or might be pregnant
- have recently had a barium test, or a scan using contrast dye or a radioactive tracer
- take calcium supplements (you may be asked not to take them on the day)
- have metal implants in your hip or spine
Where to have a bone density scan
Not every private DEXA clinic offers bone density scans — some focus on body composition only. Our city pages show which services each clinic provides, and the body composition guide explains the difference.
Frequently asked questions
Is a DEXA scan the same as a bone density scan?
A bone density scan is one use of a DEXA scanner. The same machine can also measure whole-body composition (fat, lean mass and bone), which is a different scan with a different report.
Can I get a bone density scan without seeing my GP?
Yes, most private clinics accept self-referral, though they will ask screening questions to make sure the scan is appropriate. Share the full report with your GP if it shows low bone density.
How often should a bone density scan be repeated?
That depends on your result and any treatment. Bone density changes slowly, so repeat scans are usually spaced years rather than months apart. Your GP or specialist can advise for your situation.
Find a bone density scan by city
This page is general information, not medical advice, and doesn't replace a consultation. If you're worried about your bone health or weight, speak to your GP.