| Classification | Bone mineral density by DXA | T-score |
| Normal | Within 1 SD of the mean level for a young adult reference population | −1.0 and above |
| Low bone mass (osteopenia) | Between 1 and 2.5 SD below that of the mean level for a young adult reference population | −1.0 and −2.5 |
| Osteoporosis | 2.5 or more below that of the mean level for a young adult reference population | At or below −2.5 |
| Severe or established osteoporosis | 2.5 or more below that of the mean level for a young adult reference population with fractures | At or below −2.5 with one or more fractures |