Categorization of osteoporosis, Osteopenia (low bone mass), and Normal bone mass based upon BMD measurement by DXA (or DEXA)
| Category | Bone mass |
| Normal | A value for BMD within 1 SD of the young adult female reference mean (T-score greater than or equal to -1 SD). |
| osteopenia (Low bone mass) | A value for BMD more than 1 but less than 2.5 SD below the young adult female reference mean (T-score less than -1 and greater than -2.5 SD). |
| Osteoporosis | A value for BMD 2.5 or more SD below the young adult female reference mean (T-score less than or equal to -2.5 SD). |
| Severe (established) osteoporosis | A value for BMD more than 2.5 SD below the young adult female reference mean in the presence of one or more fragility fractures. |
BMD: bone mineral density; DXA: dual-energy x-ray absorptiometry; SD: standard deviation.