Which of the following is most directly used to diagnose osteoporosis?

• A. T-score on DXA
• B. FRAX score
• C. Bone turnover markers
• D. Calcium level

Answer: (A)

Diagnosing osteoporosis relies on bone mineral density rather than risk estimates or laboratory values. A DXA scan measures bone mineral density and expresses it as a T-score, which compares the patient’s density to that of a young healthy reference population. When the T-score is -2.5 or lower, osteoporosis is diagnosed, making this the direct and standard criterion for confirming the condition.

The FRAX tool estimates fracture risk by combining BMD with clinical factors, but it does not by itself establish an osteoporosis diagnosis. Bone turnover markers reflect the rate of bone remodeling and can vary with many factors; they are not used to diagnose osteoporosis. Calcium level indicates calcium in the blood, not bone density, and is not diagnostic of osteoporosis.