Bone Density Scan
A bone density scan, also known as a DEXA or DXA scan, is a low-dose x-ray that measures calcium and other minerals in your bones.
A bone density scan, also known as a DEXA or DXA scan, is a low-dose x-ray that measures calcium and other minerals in your bones. Bones containing more minerals are denser and tend to be stronger and less likely to break. The measurement helps show your bone's strength and thickness (known as bone density or mass). Your bones usually become thinner as you get older or if you develop certain medical conditions. When bones become thinner than usual, it's known as osteopenia. Osteopenia puts you at risk for a more serious condition called osteoporosis . Osteoporosis is a disease that causes bones to become very thin and brittle. It gets worse over time. It usually affects older people and is most common in women over the age of 65. People with osteoporosis are at higher risk for fractures (broken bones), especially in their hips, spine, and wrists. Other names: bone mineral density test, BMD test, DEXA scan, DXA; Dual-energy x-ray absorptiometry scan, Bone densitometry, Dual x-ray absorptiometry, DXA
Why is this test ordered? Most women age 65 or older should have a bone density scan. Women in this age group are at high risk of losing bone density, which can lead to fractures. Women of other ages and men may also be at risk for losing bone density if they: Have a very low body weight Have had one or more fractures after the age of 50 Have lost a half inch or more in height within one year Have a family history of osteoporosis Other risk factors for losing bone density include: Lack of physical activity Long-time use of tobacco or alcohol Not getting enough calcium and vitamin D in your diet Having medical conditions such as diabetes or rheumatoid arthritis Being an older male with risk factors for weak bones or osteoporosis
Clinical Interpretation
Bone density results are often given as T-scores and Z-scores. A higher number means that you have greater bone density. The lower your score, the higher your risk of bone fracture. T-score may be used if you are a postmenopausal woman or a man age 50 or older. This measurement compares your bone density with a healthy young adult of the same sex. Z-score may be used if you are premenopausal, a male under age 50, or a child. This measurement compares your bone density measurement with other people your age, weight, sex, and ethnic or racial origin. Your T-score results may show one of the following: A T-score of -1.0 or higher. This is considered normal bone density . A T-score between -1.0 and -2.4. This means you have low bone density (osteopenia) and may be at risk for developing osteoporosis. A T-score of -2.5 or less. This means you probably have osteoporosis . If your results show you have low bone density, your provider will recommend steps to prevent further bone loss. These may include: Getting more exercise , with activities such as walking, dancing, and using weight machines. Adding calcium and vitamin D to your diet. Taking prescription medicines to increase bone density. Your provider may recommend how often you need to have repeat scans, based on your risk of bone fractures. The recommendations are to get a central DEXA scan every two years for high risk, every 3 to 5 years for moderate risk, and every 10 to 15 years for low risk. If you have questions about your results and/or treatments for bone loss, talk to your provider. Learn more about laboratory tests, reference ranges, and understanding results .
Clinical Protocol & Patient Advice
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You may be told to stop taking calcium supplements 24 to 48 hours before your test. You should also avoid wearing metal jewelry or clothes with metal parts, such as buttons or buckles.
Usage Guidance
- Reference ranges vary by laboratory. Always discuss your specific results with a qualified healthcare professional.
Source: MedlinePlus, National Library of Medicine. View the original.