If you've recently had a bone mineral density (BMD) test, you may be awash in the confusion of T-scores, Z-scores, and FRAX risk, worried you might have osteopenia or osteoporosis. Whether you've had a dual energy X-ray absorptiometry (DEXA or DXA) scan measuring hip and spine BMD or peripheral testing of heel, forearm, wrist or finger, you need to understand your bone mineral density report.
Instructions
1. Draw a number line on a sheet of paper. Put "zero" in the middle. To the right of the zero, space out positive numbers one through five (+1, +2, etc.). To the left of the zero, space out negative numbers one through five (-1, -2, etc.). Draw a vertical line through +1 and -1. Draw a vertical line through -2.5.
2. Plot your T-score from your BMD test on the number line. If you have more than one T-score (for example, one from your spine and one from your hip), use the lowest number. Remember, in negative numbers "higher is lower." A score of -2 is lower than a score of -1; a score of -3 is lower than a score of -2. The T-score is a comparison of your bone density to that of a healthy 30-year-old at the peak of bone density. The T-score is the number your doctor will use to diagnose osteoporosis.
3. Plot your Z-score on the number line. The Z-score is a comparison of your bone density to what would be normal for someone of your age and size. A Z-score above -2 (to the right of -2 on the number line) is considered normal. However, Z-scores are not used to diagnose osteoporosis, as many older people may have a normal Z-score, yet may still be at risk for fracture based on their T-score or other factors.
4. Determine whether you have osteopenia or osteoporosis based on your T-score. The further left of the zero on your number line, the more you are at risk. If your T-score falls between +1 and -1, your bone density is normal. If your T-score falls between -1 and -2.5, you have low bone density or osteopenia. If your T-score falls at -2.5 or lower, the diagnosis is osteoporosis.
5. Use the online FRAX calculation tool noted below in Resources to determine your fracture risk. Click "Calculation Tool" and choose your country. Fill out the questionnaire, using the conversion tool on the left side to calculate metric weight and height. Enter your T-score at question 12 and click "calculate" to determine your risk of major osteoporotic or hip fracture in the next 10 years. This may help you and your doctor make a decision about whether you should take osteoporosis medication.
Tags: your T-score, bone density, number line, your bone, from your, T-score falls
