How often should a DEXA (Dual-Energy X-ray Absorptiometry) scan be performed?

DEXA Scan Frequency Guidelines

DEXA scans should be performed every 2 years for standard monitoring, but high-risk individuals may require annual scans based on clinical factors and treatment status. 1

Standard Monitoring Intervals

• General population: Every 2 years for routine monitoring 1
• High-risk individuals: Every 1-2 years if there is high risk for accelerated bone loss 1
• Treatment monitoring: Every 2 years for patients on osteoporosis treatment 1
• Maximum frequency: Testing should generally not be conducted more than annually 1

Patient-Specific Monitoring Intervals

Patients requiring more frequent monitoring (annually):

• Patients receiving glucocorticoid therapy for >3 months 1
• Patients with conditions causing rapid bone loss 1
• Patients initiating therapy with medications known to adversely affect BMD 1
• Patients with advanced cirrhosis, particularly those eligible for transplantation 1

Patients requiring standard monitoring (every 2 years):

• Postmenopausal women and men ≥50 years with stable risk factors 1
• Cancer survivors on stable treatment 1
• Patients with chronic conditions but stable bone health 1

Special Populations

Cancer patients:

• Baseline DXA at diagnosis if risk factors present
• Repeat every 2 years or annually if medically indicated 1
• Do not perform more than annually 1

Spinal cord injury patients:

• Serial DXA assessment following a minimum of 12 months of therapy
• Follow-up at 1-2 year intervals 1

Liver disease patients:

• Repeat DEXA every 2-3 years for patients with normal BMD
• Annual DEXA for cholestatic patients with multiple risk factors 1

Clinical Decision Algorithm

1. Assess risk factors:

   • Age (≥65 for women, ≥70 for men)
   • Previous fragility fracture
   • Chronic medication use (glucocorticoids, anticonvulsants, etc.)
   • Medical conditions affecting bone health
   • Family history of osteoporosis

2. Determine monitoring frequency:

   • If on bone-modifying treatment → every 2 years
   • If high risk for accelerated bone loss → annually
   • If stable risk profile → every 2 years
   • If normal BMD with minimal risk factors → every 2-3 years

3. Consider treatment response:

   • If BMD decreasing despite treatment → may need more frequent monitoring
   • If stable or improving BMD → maintain standard interval

Important Considerations

• Patients should be scanned on the same DXA machine for follow-up to ensure accurate comparisons 1
• BMD values, not T-scores, should be compared between previous and current scans 1
• Scan intervals <1 year are generally discouraged as changes in BMD may not be detectable within this timeframe 1
• For premenopausal women and men <50 years, only Z-scores (not T-scores) should be reported 1

Common Pitfalls to Avoid

• Scanning too frequently (less than annually), which may not show meaningful changes in BMD
• Using different DXA machines for follow-up scans, which introduces technical variability
• Relying solely on T-scores rather than absolute BMD values when comparing serial scans
• Failing to account for degenerative changes that may artificially elevate BMD values in older patients
• Not considering specific risk factors that might warrant more frequent monitoring

By following these guidelines, clinicians can optimize the frequency of DEXA scanning to effectively monitor bone health while avoiding unnecessary testing.