A Dual-Energy X-Ray Absorptiometry (DXA) test is a bone density study used to determine whether or not you have osteoporosis or low bone mass, conditions that commonly affect women after menopause and, in some cases, men. It is a fast, safe, painless test that measures bone strength and can predict your risk for bone fracture. DXA may also be used as a follow-up procedure to monitor response to specific medications.

The DXA unit consists of a central device with a large flat table, and an "arm" suspended overhead. When measuring bone density in the spine, you lie on the table with your legs supported on a padded box to flatten the pelvis and spine. When measuring bone density in the hip, your foot will be placed in a brace designed to rotate your hip inward. In either case, the detector will slowly pass your body, generating images on a computer monitor.

You will be asked to lie very still and may be required to hold your breath for a few seconds to reduce the possibility of a blurred image. The test can take anywhere from 10 to 30 minutes, depending on the part of your body being imaged.

When preparing for your DXA screening, discontinue calcium, vitamin D, and multi-vitamin supplements for two full days prior to the exam date.

DXA is most often performed on the lower spine and hips. It also can measure vertebral height and assess possible vertebral fractures in the thoracic and lumbar spine. It is an advanced form of testing that is highly accurate and requires less radiation exposure than older methods of bone density testing.