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DEXA scan

Dr Karen Martin
Reviewed by Dr Karen MartinReviewed on 19.10.2023 | 3 minutes read

DEXA is short for 'dual energy X-ray absorptiometry' which is the medical term for a type of scan that uses mild X-rays to measure how dense bone is. The density of bone helps determine how strong the bone is, so the lower the density, the weaker the bone is considered to be. A DEXA scan can be used to diagnose conditions such as osteopenia and osteoporosis.

Osteoporosis is when your bone density is significantly lower than the normal range for your age and gender, and the bones are therefore at a higher risk of breaking easily. Osteopenia is a milder form of this with just a slightly lower than normal bone density.

Who needs a DEXA scan?

You may be referred for a DEXA scan if you have risk factors for developing osteoporosis or if you have had a bone that broke easily. For the scan, you may not need to take any clothes off depending on the area being scanned; you lie on your back on an X-ray table and the DEXA scanning machine passes over your body from above you. You will be asked to remove any metal you may be wearing, or any clothes with metal fasteners, as this can obscure the scanning. A DEXA scan is painless, takes 10 to 20 minutes to complete, and you can go home right away afterwards.

What about the radiation?

A DEXA scan does expose you to a small amount of radiation but this is very small in comparison to other types of scans such as a CT scan. The amount of radiation is so small that it doesn’t put you at any significantly higher risk of developing problems in the future such as radiation-associated cancers. However, DEXA scans are not recommended for people who are pregnant.

What do the results mean?

The results of a DEXA scan are typically reported in terms of T-scores and Z-scores, which provide information about an individual's bone density compared to that of a healthy young adult population.


  • A T-score compares an individual's bone density to that of a healthy young adult of the same sex.
  • A T-score of -1 or above is considered normal, indicating bone density within the expected range for a young adult.
  • A T-score between -1 and -2.5 indicates low bone density, known as osteopenia, which may increase the risk of developing osteoporosis.
  • A T-score of -2.5 or lower indicates osteoporosis, a condition characterized by significantly reduced bone density and increased fracture risk.


  • A Z-score compares an individual's bone density to that of people of the same age, sex, and sometimes ethnicity.
  • A Z-score within the normal range suggests bone density appropriate for the individual's age group.
  • A Z-score significantly below the expected range for the individual's age group may indicate underlying medical conditions affecting bone health, such as hormonal disorders or nutritional deficiencies.

In summary, DEXA scan results provide valuable information about an individual's bone health and fracture risk. Interpretation of the results should be done in consultation with a healthcare professional, who can provide personalized recommendations for managing bone health based on the DEXA scan findings and other clinical factors.

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This article has been written by UK-based doctors and pharmacists, so some advice may not apply to US users and some suggested treatments may not be available. For more information, please see our T&Cs.
Dr Karen Martin
Reviewed by Dr Karen Martin
Reviewed on 19.10.2023
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