DXA (previously DEXA) stands for dual energy X-ray absorptiometry. It is a very low-dose X-ray exam that measures the mass of bone in certain standard areas of your body, usually the hip, lumbar spine and sometimes forearm. The amount of bone detected is then compared to the average for a person of the same sex, age, and race.

What is a DXA (DEXA) Scan?

DXA scans are done to find low bone density. Osteoporosis is a silent disease, the first symptom of which can be a broken bone.

1 out of every 2 women and 1 out of 8 men over age 50 will have an osteoporosis-related fracture in their lifetime.

There are several groups of people who should consider bone-density testing:

• All postmenopausal women below age 65 who have risk factors for osteoporosis.
• All women 65 years and older.
• Postmenopausal women with fractures.
• Women with medical conditions associated with osteoporosis.
• Women whose decision to use medication might be aided by bone-density testing.
• Men age 70 and older.
• Men ages 50-69 with risk factors for osteoporosis.

When, and how often, you should get a bone-density scan depends on your age, risk factors and whether you’ve already been diagnosed with thinning bones. The general rule: anyone at risk for osteoporosis should get a bone-density scan. Don’t wait for a fracture or a formal diagnosis.

Generally, Medicare and many insurance companies will pay for a bone scan every two years in women with osteoporosis or who are at high risk. Because the response to treatment occurs slowly, this is usually an acceptable time interval.

Another thing to keep in mind: not all DXA scanners are created equal. There are slight differences in the calibration of different manufacturers’ machines.

Ideally you should get all your bone scans on the same DXA scanner.