DXA assessment for osteoporosis uses T-scores measured at which sites?

• A. Forearm
• B. Hip or spine
• C. Skull
• D. Whole body

Answer: (B)

The main concept is that diagnostic bone density for osteoporosis relies on sites that best reflect fracture risk and are standardized for comparison. T-scores used to define osteoporosis come from measurements at the hip (proximal femur) and the spine (lumbar region). These two sites provide the most reliable and clinically relevant information about fracture risk, and they are the reference sites used in guidelines to label osteoporosis (a T-score of -2.5 or lower).

Other sites aren’t used for the standard diagnostic threshold. Forearm BMD can be measured in certain situations when hip or spine measurements aren’t feasible, but it isn’t the primary site for diagnosing osteoporosis. The skull isn’t used because its density is influenced by degenerative changes and other factors, making it not a good predictor of osteoporotic fracture risk. Whole-body BMD is less precise and not used for diagnosing osteoporosis, as it averages many sites and doesn’t provide the focused risk information needed for clinical decisions.

So, hip or spine measurements are the best and most accepted sites for calculating the T-score in osteoporosis diagnosis.