OsteoEd

Following Changes in Bone Density

Christopher Knight, MD Literature reviewed April 17, 2006. Updated January 22, 2009

A 53-year-old woman is concerned about osteoporosis because her mother suffered a debilitating hip fracture at the age of 63. The patient is postmenopausal and started therapy with calcium and vitamin D six months ago when a DXA scan showed a T-score of -0.85. She would like another DXA scan to see how the therapy is working.

Click an answer under each question.

1. Your patient's prior DXA scan was obtained on a Hologic Incorporated instrument, and the instrument in your clinic is made by Lunar Corporation. How much variation could you see in the measured bone mineral density?

   • Option A 1 to 2 percent
   • Option B 3 to 5 percent
   • Option C 5 to 15 percent

2. How much variation is there between repeat DXA readings on the same machine?

   • Option A 1 to 2 percent
   • Option B 3 to 5 percent
   • Option C 5 to 15 percent

3. Which parameter on the bone density report should you monitor when following changes in bone density?

   • Option A T-score
   • Option B Z-score
   • Option C Percent change in bone mineral density

4. What is the average annual rate of loss of bone mass in postmenopausal women?

   • Option A 1 to 2 percent
   • Option B 3 to 5 percent
   • Option C 5 to 15 percent

5. Based on this information, when should you order a second DXA scan?

   • Option A Obtain a DXA now
   • Option B Obtain a DXA in 6 months
   • Option C Obtain a DXA in 2 to 5 years

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