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What are examples of bone density tests?

Several tests have been used to estimate the density of different bones in the body. All of these tests are painless and involve no drugs or needles.

Dual-energy X-ray absorptiometry (DXA) is the most accurate test used to help diagnose osteoporosis. This method involves a short scan of the hip or spine. The exposure to radiation is low (less than an X-ray); the cost is about $150 per bone site tested. Most DXA studies are performed at the spine, probably because spinal scans are faster and easier to perform. Nevertheless, scans of the hip are generally better. First, they provide more information. Also, they're the "gold standard"; they're used by manufacturers of DXA machines and by those who create U.S. reference standards. Also, DXA scans of the spine often produce inaccurate results for older women, who frequently have arthritic changes, calcifications (calcium deposits), or vertebral deformities that affect test results.

Single-energy X-ray absorptiometry (SXA) and peripheral dual-energy X-ray absorptiometry (pDXA) are less-expensive relatives of the DXA test that measure bone density at the heel, finger, or forearm. The exposure to radiation is low. At the present time, scientists do not know how well these two test results predict the risk of fractures.

Ultrasound densitometry measures bone density at the heel, kneecap, or other bones of the lower leg. The test is relatively inexpensive and uses sound waves rather than radiation to make its measurements. Ultrasound bone density testing has been used as an initial test for women who have the medical risk factors for osteoporosis. Most of these women will have test results high enough to show that they do not need the more expensive DXA test to measure bone density at the hip.

Single-energy photon absorptiometry is an older technique that takes 10 to 15 minutes to scan the bone of the forearm or heel and involves a very low dose of radiation.

Quantitative computed tomography (QCT) is a method used to measure the mineral content of the bones of the spine or arm. QCT is a complex and expensive test that is used mainly for research purposes.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.