Bone Density Test (DEXA Scan)

What is a Bone Density Test?

A bone density test is used to measure bone mineral content and density. It may be done using X-rays, dual-energy X-ray absorptiometry (DEXA or DXA), or a special CT scan that uses computer software to determine bone density of the hip and/or spine. The DEXA scan is considered to be the most accurate bone density test.

This measurement tells your healthcare provider if there is decreased bone mass, which means bones are more brittle and prone to break or fracture easily.

A bone density test is used mainly to diagnose osteopenia and osteoporosis. It's also used to determine your future fracture risk. The testing procedure typically measures the bone density of the bones of the spine, lower arm, and hip. Portable testing may use the radius (1 of the 2 bones of the lower arm), wrist, fingers, or heel for testing, but is not as precise as the non-portable methods because only one bone site is tested.

Standard X-rays may show weakened bones. But at the point when bone weakness can be seen on standard X-rays, it may be too far advanced to treat. Bone density testing can find decreasing bone density and strength at a much earlier stage, when treatment is more effective.

How to Prepare

Generally, no preparation is necessary for this test. You may be told to stop taking calcium supplements 24 to 48 hours before your bone density test.