Bone mineral density (BMD) testing generally correlates with bone strength and is used to diagnose osteoporosis. The BMD is measured with a dual energy x-ray absorptiometry test (referred to as a DXA scan). By measuring BMD, it is possible to predict fracture risk in the same manner that measuring blood pressure can help predict the risk of stroke. It is important to remember that BMD cannot predict the certainty of developing a fracture. It can only predict risk. It is also important to note that a bone density scan, or test, should not be confused with a bone scan, which is a nuclear medicine test that is used to detect tumors, cancer, fractures, and infections in the bone.