What are the limitations of DEXA Bone Densitometry?

• A DEXA test cannot predict who will experience a fracture but can provide indications of relative risk.
• Despite its effectiveness as a method of measuring bone density, DEXA is of limited use in people with a spinal deformity or those who have had previous spinal surgery. The presence of vertebral compression fractures or osteoarthritis may interfere with the accuracy of the test; in such instances, CT scans may be more useful.
• Central DEXA devices are more sensitive than pDEXA devices but they are also somewhat more expensive.
• A test done on a peripheral location, such as the heel or wrist, may help predict the risk of fracture in the spine or hip. These tests are not helpful in following response to treatment, however, and if they indicate that drug therapy is needed, a baseline central DEXA scan should be obtained.