A bone density test measures the amount of bone mineral content and density at specific sites (mainly the hip and the spine) that are most susceptible to fracture. The test compares your results to an established norm.
At Virginia Women’s Center, we use a technology called DXA (dual-energy X-ray absorptiometry) to measure bone density. DXA scans are performed in two of our office locations, often at the same time as your annual exam and mammogram. Learn how to prepare for your DXA scan here.
Why should I have a bone density test?
- You can learn if you have weak bones or osteoporosis and take steps to prevent breaking a bone in the future
- You can see if your bone density is improving, getting worse or staying the same
- You can measure your response to osteoporosis treatment
- If you have already broken a bone, you can determine if you have osteoporosis
Who should have a bone density scan?
- Women age 65 or older
- Men age 70 or older
- Women under age 65 with risk factors
- Men age 50-69 with risk factors
What do the results of my bone density test mean?
The results of your bone density test are reported in two numbers: a T-score and a Z-score. A T-score shows your bone density compared to that of a healthy 30 year old adult. T-scores are in units called standard deviations where a healthy 30 year old adult has a score of 0. The more standard deviations your bone density is below 0, the lower your bone density and the higher your risk of fracture.
Based on your results, your health care provider can determine if any treatment is necessary for you to prevent your risk of breaking bones in the future.
- Normal bone density = Your T-score is within one standard deviation of the young adult mean (+1 or -1). Your bone density is considered normal.
- Low bone density or osteopenia = Your T-score is between -1 and -2.5 standard deviations from the young adult mean. Your bone density is below normal and you have a greater chance of developing osteoporosis. Most women in this category do not require medication – only Calcium, Vitamin D and weight-bearing exercise.
- Osteoporosis = Your T-score is -2.5 standard deviations or below from the young adult mean. Your bone density indicates you have osteoporosis. Medication should be considered to reduce the risk of fracture.
A Z-score, also measured in standard deviations, compares your bone density to what is normal for someone your age and body size. In older adults, the Z-score can be misleading since low bone mineral density is quite common. For younger individuals, the Z-score can be helpful in determining if there is an underlying disease or condition that is causing bone loss.