Help for understanding bone density test results
[Updated June 21, 2019]
If you recently had a DEXA scan to measure your bone density, you may be confused by what the results really mean. Is low bone density an inevitable first step toward osteoporosis? Are these results telling you that you’re going to fracture? And why is your doctor using your DEXA to prescribe a bone drug — are your results that bad?
Whatever your situation, I want to reassure you that knowledge is power when it comes to your bone density test results. Not only is there a lot to know about the numbers themselves, but there are several key “ground rules” that are important to better understand bone density test results in general.
“Ground rules” for understanding more about DEXA scan results
- DEXA scan should be several pages long, have many charts and x-rays of the spine and hip. Obtain copies of your full bone density reports from your DEXA or DXA scans. You’ll want to look at all the results, not just the summary page.
- Small changes in bone mineral density are not significant. Research has shown that at least a 5-6% change on a bone density test is needed to be sure that any change is not simply due to placement on the machine.
- Bone density tests do not truly measure bone density. DXA calculates BMD using area, so it’s not an accurate measurement of true bone mineral density. Those with smaller body size and/or thin, small bones will not get a true measure of their bone density from the scan.
- Bone density changes are related to life stage. The menopause transition generally is a time of accelerated bone loss.
- Not all bone density reports are going to look exactly the same. They may look different, but the reports should all have the same elements.
- Using the same type of bone density testing machine is important for comparing results. Even better is to have the test done in the same location and even with the same operator.
- DEXA alone can’t predict fracture risk. To understand if your bones are at risk of fracture, we need to understand all your risk factors, including rate of bone loss. One snapshot of bone density is not enough to decide that you need bone drugs. [For more, read my blog, Bone density tests aren’t enough. Why a Fracture Risk Assessment is essential.]
What are the different bone density screening tests?
For more information about the different bone density screening tests, limitations of BMD testing and steps you can take to limit variability in BMD tests, see my article on bone density testing.
You can also learn more about how to read your results with my online course: How to Understand Your Bone Density Test & What it Means for You.
I’m Dr. Susan E Brown. I am a clinical nutritionist, medical anthropologist, writer and motivational speaker. Learn my time-tested 6 step natural approach to bone health in my online courses.
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