Who should get a bone density test?

  • Medical Author:
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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What is a bone density test?

Bone density testing is used to assess the strength of the bones and the probability of fracture in persons at risk for osteoporosis. The test, referred to as bone densitometry or bone mineral density scan (BMD), is a simple, noninvasive procedure that takes just minutes.

Unlike a bone scan, bone densitometry testing does not involve the administration of radioactive contrast material into the bloodstream.

How is a bone density test done?

The most commonly used test is known as a dual energy X-ray absorptiometry (DEXA) scan, and it can be performed with devices that measure bone density in the hip and spine, or smaller peripheral devices to measure bone density in the wrist, heel, or finger. The central bone density device is used in hospitals and medical offices, while the smaller peripheral device is available in some drugstores and in screening sites in the community. The DEXA scan involves a much smaller radiation exposure than a standard chest X-ray.

What causes osteoporosis (bone loss)?

In premenopausal women, estrogen produced in the body maintains bone density. Following the onset of menopause, bone loss increases each year and can result in a total loss of 25%-30% of bone density in the first five to ten years after menopause. Your doctor can help you decide when and if you need a bone density test. In general, this testing is recommended for women 65 and older along with younger postmenopausal women who have further risk factors for osteoporosis, including:

Bone density test results

Your bone density measurement will be compared to the average peak bone density of young adults of the same sex and race. The results are usually reported as a "T score" and a "Z score." The T score compares your bone density with that of healthy young women, while the Z score is a comparison of your bone density with that of other people of the same age, gender, and race.

In either the T or Z score, a negative number means you have thinner bones than the standard. The more negative the number, the greater the degree of bone loss.

Osteoporosis is defined as the beginning of bone loss and corresponds to a T score of -1 to -2.5. A T score lower than -2.5 is indicative of osteoporosis.

For more information, please read the following MedicineNet article:

Medically reviewed by Aimee V. HachigianGould, MD; American Board of Orthopaedic Surgery

REFERENCE:

"Bone tumors: Diagnosis and biopsy techniques"
UpToDate.com


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Reviewed on 1/11/2017

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