Dual energy X-ray absorptiometry (DEXA) measures the density of your bones to see if you have osteoporosis, a bone-thinning disease.
The DEXA scan is an x-ray scan that uses a small amount of radiation to take pictures of different bones. These pictures are used to measure the density of the bones at the spine, hip and forearm. It can also take pictures of other bones such as a finger or the heel bone. Measurements of the spine and hip are called central DXA. Those done on the arms or legs are called peripheral DXA. In some cases, your doctor may order a whole body scan.
The DEXA Test
Prep for a DEXA Scan
- Eat normally on the day of the test.
- 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
Central DXA measures bone density in the hip and spine. You will be asked to lie on a table. Your position will depend on the area being examined. You will be asked to hold still and may be asked to hold your breath while the X-ray is taken. The X-ray will be taken and sent to a computer monitor.
Peripheral DXA measures bone density in the finger, hand, forearm or foot. The area being examined will be placed in a small device. The device will provide a bone density reading in a few minutes.
After the DEXA Scan
You will be able to leave after the test is done. It will take about 10 minutes and will not hurt.
The test results are usually available within a few days. Your test results will show two types of scores:
- T score—This number shows the amount of bone you have in comparison to a young adult of the same gender with peak bone mass. A score above -1 is considered normal. A score between -1 and -2.5 may mean you have osteopenia, the first stage of bone loss. A score below -2.5 means you may have osteoporosis.
- Z score—This number shows the amount of bone you have in comparison to other people of your age group, gender, and race. A score below -2 is considered abnormal.
These test results will help your doctor determine your risk for bone fractures.
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.