Bone densitometry, which is known as dual energy X-ray absorptiometry, also called DXA or DEXA, is a test that calculates bone density quickly and accurately. Used to discover osteopenia or osteoporosis, the test uses a very small dose of ionizing radiation to take pictures inside the body, normally the lower spine and hip, to measure bone loss. Osteopenia and osteoporosis cause the bone to lose minerals and density, which increases the possibility of fractures. While the bone densitometry test is often recommended after age 60, it can be prescribed earlier in cases where reduced bone density is presenting or suspected. DEXA is the most accurate way to diagnose osteoporosis and osteopenia.