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Bone mineral density test
BMD test; Bone density test; Bone densitometry; DEXA scan; DXA; Dual-energy x-ray absorptiometry; p-DEXA; Osteoporosis-BMD
A bone mineral density (BMD) test measures how much calcium and other types of minerals are in an area of your bone.
This test helps your health care provider detect osteoporosis and predict your risk of bone fractures.
Osteoporosis
Osteoporosis is a disease in which bones become fragile and more likely to break (fracture).
How the Test is Performed
Bone density testing can be done several ways.
The most common and accurate way uses a dual-energy x-ray absorptiometry (DEXA) scan. DEXA uses low-dose x-rays . (You receive more radiation with a chest x-ray.)
x-rays
X-rays are a type of electromagnetic radiation, just like visible light. An x-ray machine sends individual x-ray particles through the body. The im...
There are two types of DEXA scans:
- Central DEXA. You lie on a soft table. The scanner passes over your lower spine and hip. In most cases, you do not need to undress. This scan is the best test to predict your risk of fractures.
- Peripheral DEXA (p-DEXA). These smaller machines measure the bone density in your wrist, fingers, leg, or heel. These machines are in health care offices, pharmacies, shopping centers, and at health fairs.
How to Prepare for the Test
If you are or could be pregnant, tell your provider before this test is done.
How the Test Will Feel
The scan is painless. You need to remain still during the test.
Why the Test is Performed
Bone mineral density (BMD) tests are used to:
- Diagnose bone loss and osteoporosis
- See how well osteoporosis medicine is working
- Predict your risk of future bone fractures
You should have bone mineral testing or screening if you have an increased risk of osteoporosis. You are more likely to get osteoporosis if you are:
- A woman, age 65 or older
- A man, age 70 or older
Women under age 65 and men ages 50 to 70 are at increased risk of osteoporosis if they:
- Have a broken bone caused by normal activities, such as a fall from standing height or lower (fragility fracture)
-
Have chronic
rheumatoid arthritis
,
chronic kidney disease
, or eating disorders
Rheumatoid arthritis
Rheumatoid arthritis (RA) is a long-term disease. It leads to inflammation of the joints and surrounding tissues. It can also affect other organs....
ImageRead Article Now Book Mark ArticleChronic kidney disease
Chronic kidney disease is the slow loss of kidney function over time. The main job of the kidneys is to remove wastes and excess water from the body...
ImageRead Article Now Book Mark Article -
Have early
menopause
(either from natural causes or surgery)
Menopause
Menopause is the time in a woman's life when her periods (menstruation) stop. Most often, it is a natural, normal body change that most often occurs...
ImageRead Article Now Book Mark Article - History of hormone treatment for prostate cancer or breast cancer
-
Have had a significant loss of height due to
compression fractures of the back
Compression fractures of the back
Compression fractures of the back are broken vertebrae. Vertebrae are the bones of the spine.
ImageRead Article Now Book Mark Article - Smoke
- Have a strong family history of osteoporosis
- Take corticosteroid medicines (prednisone or methylprednisolone) every day for more than 3 months
- Take thyroid hormone replacement
- Have three or more drinks of alcohol a day on most days
Current practice recommends BMD retesting every 2 years. However, some women may be able to wait a much longer time between their screening tests. Talk to your provider about how often you should be tested.
Normal Results
The results of your test are usually reported as a T-score and Z-score:
- T-score compares your bone density with that of a healthy young women.
- Z-score compares your bone density with that of other people of your age, gender, and race.
With either score, a negative number means you have thinner bones than average. The more negative the number, the higher your risk of a bone fracture.
A T-score is within the normal range if it is -1.0 or above.
What Abnormal Results Mean
Bone mineral density testing does not diagnose fractures. Along with other risk factors you may have, it helps predict your risk of having a bone fracture in the future. Your provider will help you understand the results.
If your T-score is:
- Between -1 and -2.5, you may have early bone loss (osteopenia).
- Below -2.5, you likely have osteoporosis.
Treatment recommendation depends on your total fracture risk. This risk can be calculated using the FRAX score. Your provider can tell you more about this. You can also find information about FRAX online.
Risks
Bone mineral density uses a slight amount of radiation. Most experts feel that the risk is very low compared with the benefits of finding osteoporosis before you break a bone.
References
Berry SD, Samelson EJ, Pencina MJ, et al. Repeat bone mineral density screening and prediction of hip and major osteoporotic fracture. JAMA . 2013;310:1256-62. PMID: 24065012 www.ncbi.nlm.nih.gov/pubmed/24065012 .
Committee on Practice Bulletins-Gynecology, The American College of Obstetricians and Gynecologists. ACOG Practice Bulletin 129. Osteoporosis. Obstet Gynecol . 2012;120:718-34. PMID: 22914492 www.ncbi.nlm.nih.gov/pubmed/22914492 .
De Paula FJA, Black DM, Rosen CJ. Osteoporosis and bone biology.In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, eds. Williams Textbook of Endocrinology . 13th ed. Philadelphia, PA: Elsevier Saunders; 2016: chap 29.
Gourlay ML, Fine JP, Preisser JS, et al. Bone-density testing interval and transition to osteoporosis in older women. N Engl J Med . 2012 Jan 19;366(3):225-33. PMID: 22256806 www.ncbi.nlm.nih.gov/pubmed/22256806 .
National Osteoporosis Foundation. Clinician's Guide to Prevention and Treatment of Osteoporosis. Washington, DC: National Osteoporosis Foundation; 2014.
U.S. Preventive Services Task Force. Screening for osteoporosis: recommendation statement. Am Fam Physician . 2011;83:1197-200. PMID: 21568254 www.ncbi.nlm.nih.gov/pubmed/21568254 .
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Bone density scan - illustration
A bone density scan measures the density of bone in a person. The lower the density of a bone the higher the risk of fractures. A bone scan, along with a patient's medical history, is a useful aid in evaluating the probability of a fracture and whether any preventative treatment is needed. A bone density scan has the advantage of being painless and exposing the patient to only a small amount of radiation.
Bone density scan
illustration
-
Osteoporosis - illustration
Osteoporosis is a condition characterized by progressive loss of bone density, thinning of bone tissue and increased vulnerability to fractures. Osteoporosis may result from disease, dietary or hormonal deficiency or advanced age. Regular exercise and vitamin and mineral supplements can reduce and even reverse loss of bone density.
Osteoporosis
illustration
-
Osteoporosis - illustration
Osteoporosis is a condition characterized by progressive loss of bone density, thinning of bone tissue and increased vulnerability to fractures. Osteoporosis may result from disease, dietary or hormonal deficiency or advanced age. Regular exercise and vitamin and mineral supplements can reduce and even reverse loss of bone density.
Osteoporosis
illustration
-
Bone density scan - illustration
A bone density scan measures the density of bone in a person. The lower the density of a bone the higher the risk of fractures. A bone scan, along with a patient's medical history, is a useful aid in evaluating the probability of a fracture and whether any preventative treatment is needed. A bone density scan has the advantage of being painless and exposing the patient to only a small amount of radiation.
Bone density scan
illustration
-
Osteoporosis - illustration
Osteoporosis is a condition characterized by progressive loss of bone density, thinning of bone tissue and increased vulnerability to fractures. Osteoporosis may result from disease, dietary or hormonal deficiency or advanced age. Regular exercise and vitamin and mineral supplements can reduce and even reverse loss of bone density.
Osteoporosis
illustration
-
Osteoporosis - illustration
Osteoporosis is a condition characterized by progressive loss of bone density, thinning of bone tissue and increased vulnerability to fractures. Osteoporosis may result from disease, dietary or hormonal deficiency or advanced age. Regular exercise and vitamin and mineral supplements can reduce and even reverse loss of bone density.
Osteoporosis
illustration
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Osteoporosis
(Alt. Medicine)
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Osteoporosis
(In-Depth)
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Hyperparathyroidism
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Diabetes - type 1
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Back pain and sciatica
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Prostate cancer
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Review Date: 11/5/2015
Reviewed By: Cynthia D. White, MD, Fellow American College of Obstetricians and Gynecologists, Group Health Cooperative, Bellevue, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
