Bone Density Scan (DEXA)

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Dual energy X-ray absorptiometry (DEXA) measures the density of your bones to see if you have osteoporosis, a bone-thinning disease. This X-ray scan uses a small amount of radiation to take pictures of bones in the spine, hip and forearm. 

normal bone compared to osteoporosis
Osteoporosis Copyright © Nucleus Medical Media, Inc.

How to Prep for a DEXA Scan

You should:

  • Eat normally on the day of the scan.
  • Wait up to 2 weeks before having a DEXA scan if you have had a barium study or if you have been injected with contrast dye for a CT scan or MRI.
  • Wear loose, comfortable clothing. Do not wear clothing with metal zippers, belts or buttons.
  • If there is any possibility that you are pregnant, let the staff know.

The DEXA Procedure 

You might have a whole-body scan or of:

  • Your hip and spine, also known as Central DEXA, which requires lying on a table
  • Your finger, hand, forearm or foot, also known as Peripheral DEXA, which uses a small device

Neither procedure hurts. These scans only take a few minutes.

How to Read Your DEXA Scan Results  

Your scan results will show two types of scores. Together they provide a picture of your risk for breaking bones.

T Score

This number compares the amount of bone you have to a young adult of the same gender with peak bone mass.

  • Over -1 = Normal bone density
  • Between -1 and -2.5 = You might have osteopenia, the first stage of bone loss 
  • Below -2.5 = You may have osteoporosis

Z Score

This number compares the amount of bone you have to other people of your age group, gender and race.

A score below -2 is considered abnormal.


Content was created using EBSCO’s Health Library. Edits to original content made by Rector and Visitors of the University of Virginia. This information is not a substitute for professional medical advice.