From the Guidelines
The test to order for bone density assessment is a Dual-Energy X-ray Absorptiometry (DEXA or DXA) scan, as it is the gold standard for measuring bone mineral density and diagnosing osteoporosis or osteopenia 1. This non-invasive test typically takes about 10-20 minutes to complete and involves lying on a padded table while a scanner passes over your body, usually focusing on the hip and spine as these are common fracture sites. The test exposes patients to minimal radiation (less than a standard chest X-ray) and provides T-scores that compare bone density to that of a healthy young adult, with scores below -1.0 indicating decreased bone density.
Key Points to Consider
- DEXA scans are recommended for women 65 and older, men 70 and older, younger postmenopausal women with risk factors, and anyone with certain medical conditions or taking medications that affect bone health 1.
- The test works by measuring how bone absorbs photons generated by very low-dose X-rays, with denser bones absorbing more photons, allowing for precise measurement of bone mineral content.
- Other screening tests, such as quantitative ultrasonography and vertebral fracture assessment, may be used in certain situations, but DEXA remains the most widely accepted and recommended test for bone density assessment 1.
- Recent guidelines continue to support the use of DEXA scans for bone density assessment, with updates emphasizing the importance of accurate scan acquisition, analysis, and interpretation 1.
Benefits and Limitations
- DEXA scans have been shown to be effective in identifying individuals at risk for osteoporotic fractures and monitoring changes in bone density over time 1.
- However, DEXA scans may not be suitable for all patients, and alternative screening tests may be necessary in certain situations, such as in patients with severe mobility issues or those who are unable to undergo DEXA scanning 1.
From the Research
Bone Density Testing
To test for bone density, the following options are available:
- Dual-energy X-ray absorptiometry (DXA) is a widely used and accepted method for measuring bone mineral density (BMD) 2, 3, 4, 5.
- DXA scans are used to assess fragility-fracture risk and guide decisions regarding pharmacologic treatment for osteoporosis 3.
- Computed Tomography (CT) scans can also be used to measure bone density, with Hounsfield units (HU) values correlated with BMD and T-scores measured by DXA 6.
Advantages of DXA
The advantages of using DXA for bone density testing include:
- Ability to predict fracture risk 2.
- Proven effectiveness in targeting antifracture treatments 2.
- Wide availability and acceptance as a standard-of-care screening tool 3.
- Ability to monitor changes in BMD over time 3.
Alternative Methods
Alternative methods for measuring bone density include: