What Do The Bone Mineral Density Measurements Indicate?
Bone mineral density measurements are extremely important to determine the condition of your bone. There are various tests to identify osteoporosis, determine your risk for fractures, and measure your response to osteoporosis treatment. Dual-energy x-ray absorptiometry, or DXA test is the most commonly used test to measure bone density at your hip and spine.
Bone mineral density measurements give you an idea about your bone mineral density and compare it to that of an established norm or standard to give you a score. Although no bone density test gives 100 per cent accurate results, the DXA test is the single most important predictor of whether a person will have osteoporosis in the future.
The T-Score and the Z-Score gives a clear idea about the condition of the bones. In T-Score, your DXA test results are compared to the ideal or peak bone mineral density of a healthy 30-year-old adult. A score of 0 indicates your bone mineral density is equal to the norm for a healthy young adult. Differences between your BMD and that of the healthy young adult norm are measured in units called standard deviations (SDs). A T-score between +1 and –1 is considered normal whereas, a T-score between –1 and –2.5 indicates that you have low bone mass and you might develop osteoporosis. A T-score of –2.5 or lower indicates that you have osteoporosis.
The z-score is evaluated in a different way. Your bone mineral density is compared to that of a typical individual whose age is similar to yours. A Z-score less than -1.5 might indicate the presence of an underlying disease or condition which can cause bone loss.
These bone mineral density measurements are useful for doctors to confirm a diagnosis of osteoporosis and to monitor osteoporosis treatment.