in
BOX 1
Using dual-energy x-ray absorptiometry scanning for diagnosis of osteoporosis
The World Health Organization international reference standard for osteoporosis diagnosis is a T-score of –2.5 or lower at the femoral neck. The reference standard from which the T-score is calculated is the National Health and Nutrition Examination Survey (NHANES) III database for white women between the ages of 20 and 29 years.
Osteoporosis may be diagnosed in postmenopausal women and in men age 50 years and older if the T-score of the lumbar spine, total hip, or femoral neck is –2.5 or lower. In certain circumstances, the 33% radius (also called the one-third radius) may be used. Skeletal sites to measure with dual-energy x-ray absorptiometry scanning (DXA):
- Bone mineral density (BMD) at both the posteroanterior spine and hip in all patients
- Forearm BMD under the following circumstances:
- Hip and/or spine cannot be measured or findings for them cannot be interpreted
- Hyperparathyroidism
- Very obese patients (over the weight limit for the DXA table)
Use all evaluable vertebrae and exclude only vertebrae that are affected by local structural change or artifact. Use three vertebrae if four cannot be used, and two if three cannot be used. BMD-based diagnostic classification should not be made using a single vertebra.
Adapted from 2007 official positions & pediatric official positions of the International Society for Clinical Densitometry with permission [8].
Other Resources: