Bone Health Tests

Updated 
May 15, 2017

Organizations like the National Institutes of Healthinfo-icon call low bone densityinfo-icon, or osteoporosisinfo-icon, the “silent disease” because there are no symptoms to watch for. Most cases of osteoporosis are diagnosed after a broken bone or fracture. But there are tests for bone mineral density. The U.S. Preventative Services Task Force recommends that all women get tested at age 65 and continue to get tests in the years after. If you are under 65 but have had breast cancer treatments that can result in bone loss you should ask your doctors if they would recommend getting tested earlier.

DEXA scan

The most common test for bone mineral density is the Dual Energy X-ray Absorptiometry scaninfo-icon, usually called the DEXA or DXA scan. In this painless test, a machine scans your body to look at the bones in your wrist, spine and hip while you lay on a table. This will provide information about your bones and is used to diagnose osteoporosisinfo-icon.

The machine never touches you but you must remain very still while the scan is being done. You may be asked to stop taking certain supplements and medicines in the day or two before being scanned and no metal jewelry, metal buttons or zippers can be worn during the scan.

Your T-Score

The results from your DEXA scaninfo-icon will include your T-score. This number compares your bone mineral density with that of a healthy 30-year-old and is the most important measure in determining whether you have osteoporosisinfo-icon or low bone densityinfo-icon. A T-score of zero would mean your bone density is the same as your doctors would expect for a person whose bones are at their strongest. Your results will place you in one of three categories depending on your score:

  • Normal, if your T-score is between +1 and -1
  • Osteopeniainfo-icon, or low bone density, if your T-score is between -1 and -2.5
  • Osteoporosis, if your score is less than -2.5

Along with your T-score, your doctor will use other information from your scan, your medical history and a physical exam to tell your risk of getting a fracture. With this information you can talk about lifestyle changes you can make to improve your bone health and possible medicines to maintain your bone strength if you are found to have osteoporosis.

Other Scores From Your Dexa Scan

Your T-score will be the main factor in telling if you have osteoporosisinfo-icon, but your DEXA scaninfo-icon results will have other scores your doctor may review with you. The bone mineral density score will tell how much tissueinfo-icon your bones contain per centimeter. The Z-score will compare your bone densityinfo-icon to what would be expected for a woman the same age as you.

Bone Scans Versus DEXA Scans

If you have metastaticinfo-icon breast cancer, or your doctors want to make sure you do not have metastatic breast cancer, they may order a different kind of test that is usually called a bone scaninfo-icon. Because the names are similar the two tests are sometimes confused. A bone scan will look for areas of too much cellinfo-icon activity in the bone to determine if the cancer has spread to the bones. A bone densityinfo-icon scaninfo-icon, or a DEXA scan, is used to check for osteoporosisinfo-icon and bone loss.

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Article May 15, 2017
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