DEXA scan: bone density testing explained
A DEXA scan, also called a bone density scan, measures bone mineral density. It is used to assess the risk of osteoporosis and fractures. In UK primary care, DEXA results are interpreted alongside risk factors such as age, menopausal status, previous fractures, steroid use and family history.
This page explains who a DEXA scan is for, what the results mean, and what typically happens next.
These articles are intended as educational sources, not diagnostic nor taking place of a proper medical assessment. If you need help or advice on medical scans, please book a GP appointment.
What a DEXA scan measures
DEXA stands for dual-energy X-ray absorptiometry. The scan uses very low-dose X-rays to measure bone density, usually at the hip and lower spine.
The goal is not to diagnose pain. It is to assess fracture risk and help guide prevention and treatment decisions.
Who may be offered a DEXA scan
A GP may consider a DEXA scan when someone has a higher risk of osteoporosis or fracture. Examples include:
- A previous low-trauma fracture, for example after a simple fall
- Long-term oral steroid use (such as prednisolone)
- Early menopause or prolonged low oestrogen states
- A strong family history of osteoporosis or hip fracture
- Low body weight or significant weight loss
- Conditions associated with bone loss, such as malabsorption or inflammatory disease
- Certain long-term medications that affect bone health, depending on the clinical context
Not everyone needs a scan. In some cases, treatment is recommended based on risk factors alone, especially after a fragility fracture.
Common symptoms and misconceptions
Osteoporosis is often called a “silent” condition because it usually causes no symptoms until a fracture occurs.
A DEXA scan does not typically explain:
- General aches and pains
- Back pain without other concerning features
- Joint stiffness due to osteoarthritis
However, new severe back pain, height loss, or a stooped posture can sometimes suggest vertebral compression fractures and should be assessed clinically.
What happens during a DEXA scan
A DEXA scan is quick and painless. You lie on a scanning table while the machine measures bone density at specific sites.
Most scans take around 10 to 20 minutes.
You can usually eat and drink normally beforehand. You may be advised to avoid calcium supplements on the day of the scan, depending on the provider.
Is a DEXA scan safe?
DEXA uses a very low dose of radiation. In general, the radiation exposure is small and the test is considered safe when clinically indicated.
If you are pregnant or could be pregnant, tell the scanning team before the scan.
Understanding DEXA results: T-score and Z-score
DEXA results are usually reported as a T-score and sometimes a Z-score.
T-score
The T-score compares your bone density to that of a healthy young adult.
A typical interpretation is:
- Normal: T-score of -1.0 or above
- Osteopenia (lower than average bone density): T-score between -1.0 and -2.5
- Osteoporosis: T-score of -2.5 or lower
A lower T-score suggests lower bone density and higher fracture risk.
Z-score
The Z-score compares your bone density to others of the same age and sex.
A low Z-score may prompt a GP to consider whether there are secondary causes of bone loss, depending on the wider clinical picture.
How GPs use DEXA alongside fracture risk tools
DEXA results are not interpreted in isolation. A GP also considers overall fracture risk using tools such as FRAX, which estimate the likelihood of fractures based on:
- Age and sex
- Previous fractures
- Smoking and alcohol intake
- Steroid use
- Rheumatoid arthritis and other risk factors
- Bone density, where available
This combined approach helps guide decisions about lifestyle changes, supplementation, and prescription treatments.
What happens after a DEXA scan
If bone density is normal
A GP may recommend:
- Maintaining strength and balance activity
- Adequate calcium intake through diet
- Vitamin D supplementation if appropriate
- Review of risk factors and medications
If osteopenia is found
Management depends on overall fracture risk. A GP may advise:
- Strength and resistance exercise
- Falls prevention
- Reviewing contributing factors such as smoking, alcohol, or low BMI
- Vitamin D and dietary calcium guidance
- Follow-up scanning in selected cases
If osteoporosis is found
A GP will consider:
- Whether treatment is recommended to reduce fracture risk
- Reviewing secondary causes
- Falls prevention and lifestyle measures
- Medication options where clinically appropriate
- Follow-up planning based on individual risk
Investigations that may be considered alongside DEXA
If osteoporosis is suspected or confirmed, a GP may consider blood tests to look for contributing factors, depending on the situation, such as:
- Calcium, phosphate and vitamin D
- Kidney function
- Thyroid function
- Full blood count
- Inflammatory markers in selected cases
Not everyone needs extensive testing. Decisions are individual and based on risk factors and history.
When to seek GP review
Consider GP review if:
- You have a DEXA result you would like explained
- You have risk factors for osteoporosis and are unsure if you need a scan
- You have had a low-trauma fracture
- You are on long-term steroids or other medicines that may affect bone density
- You have concerns about falls, balance, or recurrent injuries
Further Reading and Hub Links
Visit our Imaging hub or browse more health topics in the AccessGP Knowledge Base.
If you are concerned about osteoporosis risk, have had a fracture, or want help interpreting a bone density result, our clinicians can advise on the safest next steps.
Last reviewed by Dr Zamiel Hussain, GMC registered GP
Updated: 23 December 2025