NATIONAL OSTEOPOROSIS FOUNDATION
Susan Allison, RNC, BSN, MPA responded:
Dear megmo84,
A Z-score compares your bone density to what is normal for someone your age. While a Z-score alone is not used to diagnose osteoporosis in premenopausal women, it can provide important information. Here are some tips to help you understand your Z-score:
*If your Z-score is above -2.0, your bone density is considered within the ranges expected for your age or normal according to the International Society for Clinical Densitometry (ISCD). For example, a Z-score of 0.5, -0.5 and -1.5 is considered normal for most premenopausal women.
*If your Z-score is -2.0 or lower, your bone density is considered below the expected range. Examples are -2.1, -2.3 and -2.5. If your Z-score is in this range, your healthcare provider will consider your health history and possible causes of bone loss, including secondary osteoporosis, before making a diagnosis of osteoporosis.
*If your Z-score is normal, but you've broken one or more bones from a minor injury, your healthcare provider may diagnose you with osteoporosis because some people with normal bone density break bones easily. As mentioned above, a bone density test will also show a T-score. A T-score compares bone density to what is normal in a healthy 30-year-old adult.