A bone mineral density test is a common test to diagnose osteoporosis, and to estimate your future chances for fracture. It's a kind of X-ray that shows the hardness of your bones. The most common type is called a dual-energy X-ray absorptiometry (DXA or DEXA). Usually, the scans look at the weight-bearing ability of your hip and spine. The results help you doctor decide if you might benefit from treatments.
A normal bone density is a T-score of plus one (+1) to a score of a minus one (-1). A low bone mass (osteopenia) is a bone density T-score of -1 to -2.5. Osteoporosis is defined as a bone density score of -2.5 or below.