Published on 14 July 2026
Below are questions you may have relating to the DEXA scan which measures bone density and is useful in identifying osteoporosis.
How accurate is a DEXA scan?
DEXA scans are highly accurate and considered to be excellent in diagnosing osteoporosis through precise measuring of bone mineral density. Extreme body sizes can affect the accuracy of the algorithm provided.
While very reliable for tracking trends over time, individual results can be affected by factors such as hydration.
What do DEXA scan results mean?
Scan results are generally shown as T-scores which compare your bone density to a healthy young adult.
A score above -0.1 is normal while a score of -0.1 to -2.5 suggests low bone mass called osteopenia, and -0.25 or lower indicates osteoporosis.
The Z-score relates to the comparison of your bone density to others of the same age, sex and size. A Z-score below -2.0 usually indicates a cause other than ageing – perhaps medication side effects, or various health conditions. The Z-score is useful for children and premenopausal women.
The Trabecular Bone Score (TBS) is used with the evaluation of the microarchitecture of the bone to further assess fracture risk.
The FRAX Score (Fracture Risk Assessment shows the likelihood of a bone fracture in the next 10 years based on the scan results and other risk factors.
How do age and gender affect DEXA scan results?
Your age and gender significantly influence DEXA scan results as they are primary factors in determining bone mineral density, peak bone mass, and the rate of bone loss.
Generally, women have lower bone mass and a higher risk of fracture than men, particularly after the menopause.
Bone density for both men and women peaks around the age of 30 after which it gradually declines.
How do you know if you are at higher risk of bone fractures?
You are likely to be at higher risk of fractures if you have a history of frequent falls – more than three annually, are elderly or have a very low bone mass: a T-score lower than -3.
What happens after you receive your scan results?
Depending on your results, clinicians may recommend increased intake of calcium and vitamin D, suggest weight-bearing exercise, calculate your bone fracture risk, and prescribe medication if osteoporosis is diagnosed.
How often should a DEXA scan be conducted?
Every one to two years if you have osteoporosis or are receiving osteoporosis treatment, between two and five years if you have low bone density (osteopenia), and between five and ten years if the scan is normal – you might not need regular follow-ups unless risk factors change.
Can lifestyle changes improve future DEXA scan results?
Yes, a heathy lifestyle can result in positive changes. Consideration can be given to resistance and weight-bearing exercise, improved nutrition, good regular sleep and the maintaining of a healthy body weight. Avoided should be bone-depleting habits such as smoking and excess alcohol, very low-calorie diets, and chronic inactivity.
How to prepare for your scan
- Do not take calcium supplements for at least 24 hours before your appointment.
- Eat and drink as usual but avoid caffeine for 24 hours before the appointment.
- Wear comfortable clothing with no metal components.
- Remove jewellery and removable metal items.
- Tell the clinical team if you have had recently a CT scan or X-ray with contrast dye, or a barium study.
- If there is a chance you might be pregnant, inform the clinical team before the appointment.
- Avoid heavy exercise immediately before the scan.
- If your DEXA scan is for fat and muscle analysis, ensure you are hydrated but do not drink large amounts right before the appointment and avoid heavy meals immediately beforehand.
How safe are DEXA scans?
The DEXA scan uses low dose dual-energy X-ray absorptiometry which is very safe. It uses a much lower level of radiation than standard X-rays.
However, bone density scans and X-rays are not recommended for women who are or might be pregnant. X-rays can damage the unborn child.
How can I access a DEXA scan at Benenden Hospital?
To arrange a DEXA scan at our hospital, you’ll need a referral from a healthcare professional. This could be your own GP, through our Private GP service or from a consultant or osteopath. Please note, it is not suitable for anyone under the age of 20 or those who have had a baby in the last 12 months.
For more information, or to book, please contact our Imaging department on 01580 362887.