When you have a bone mineral density test,
You will get the result of your BMD test in a special number called a T-score. It stands for "standard deviations" or "SD." It indicates how much your bone density is above or below normal.
Healthcare providers use the T-score to diagnose osteoporosis. If more than one bone is tested, they use the lowest T-score to make a diagnosis of osteoporosis. The World Health Organization (WHO) has defined the T-scores and what they mean.
What your T-score means:
The lower a person's T-score, the lower the bone density. A T-score of -1.0 is lower than a T-score of 0.5; a T-score of -2.0 is lower than a T-score of -1.5; and a T-score of -3.5 is lower than a T-score of -3.0.
For most BMD tests, 1 SD difference in a T-score equals a 10-15 percent decrease in bone density. For example, a person with a T-score of -2.5 has a 10-15 percent lower BMD than a person with a T-score of -1.5.
Your BMD test result also includes a Z-score that compares your bone density to what is normal in someone your age and body size. Healthcare providers do not use Z-scores to diagnose osteoporosis in postmenopausal women and men age 50 or older. Among older adults low bone mineral density is common, so Z-scores can be misleading. An older person might have a "normal" Z-score but still be at high risk for breaking a bone.
recommend using Z-scores rather than T-scores for younger men, premenopausal
women and children. However, healthcare providers often use
The University of Arizona College of Public Health / The University of Arizona Cooperative Extension / The University of Arizona College of Agriculture & Life Sciences / Maricopa Co. Cooperative Extension Family & Consumer Sciences / The University of Arizona Dept of Nutritional Sciences /Arizona Osteoporosis Coalition
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