Bone Mineral Density (BMD) Test
Type: Axial Extremity
What is a Bone Mineral Density Test?
This test is a low-dose x-ray of the hip, spine, and/or forearm that measures your bone density.
The lower the density of a bone; the higher the risk that a bone will break. An extra spine image
may be done to assess spine fractures. A bone density scan is painless. It takes about 40
minutes. The radiation dose is very small, about 1/5th of a chest x-ray.
Why Have a Bone Density Test?
Diagnose osteoporosis (a disease in which bones become fragile and more likely to break).
Detect bone loss, from taking steroids (for example, prednisone) or other medicines.
Measure changes in bone density over time.
Help decide on treatment options for low bone density
Monitor response to osteoporosis medication.
How to Prepare for the Test
Tell your health care provider if you may be pregnant.
It is okay to eat and drink before the test.
Do not take calcium pills or chewable tablets within 12 hours before the test.
This includes TUMS® or other antacids.
Do not wear clothes with metal such as buckles, rivets, buttons, zippers or under wire bras.
During the Test
You will lie on an exam table for a spine and hip images. You may need to lie onyour side for a
different view of your spine. You may need to sit in a chair for a forearm test. You will be
asked to remain still during the imaging. You will be in an open space. A bone density
technologist will be with you during the test.
In some cases, the technologist will need to confer with the doctor who is reading the scan by
phone. A phone call to the doctor is not a cause for alarm, just a need for more information.
Your bone density is compared to standards, or norms, known as “age matched” and “young
normal”. The age-matched reading compares your bone density to what is expected in someone
of your age, sex, and size. The young normal reading compares your results to the best peak
bone mass of a healthy young adult of the same sex. The health care provider that ordered this
test will report the results to you.
Reference: National Osteoporosis Foundation: www.NOF.org
Your health care team may have given you this information as part of your care. If so, please use it and call if you
have any questions. If this information was not given to you as part of your care, please check with your doctor. This
is not medical advice. This is not to be used for diagnosis or treatment of any medical condition. Because each
person’s health needs are different, you should talk with your doctor or others on your health care team when using
this information. If you have an emergency, please call 911. Copyright ©5/2015. University of Wisconsin Hospitals
and Clinics Authority. All rights reserved. Produced by the Department of Nursing. HF#5646.