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

DEXA Scan Frequency Recommendations

For most patients, DEXA scans should be repeated every 2 years, with annual scanning reserved for high-risk individuals on bone-depleting medications or with conditions causing accelerated bone loss. 1

Standard Frequency Guidelines

The fundamental principle is that BMD measurements should not be conducted more frequently than once per year, as bone density changes occur slowly and intervals less than 1 year rarely provide clinically meaningful information due to measurement variability. 1, 2

General Population Intervals

• Patients with normal BMD or mild osteopenia without additional risk factors: Repeat DEXA every 2 years 1
• Patients with moderate to severe osteopenia (T-score ≤ -2.0): Repeat DEXA every 2 years 2
• Patients with established osteoporosis on stable treatment: Repeat DEXA every 2-3 years 3

High-Risk Patients Requiring Annual Monitoring

Annual DEXA scanning (every 1-2 years) is indicated for patients with:

• Glucocorticoid therapy for >3 months 4, 1, 2
• Cancer treatments affecting bone (aromatase inhibitors, androgen deprivation therapy, chemotherapy-induced ovarian failure) 2
• Medications adversely affecting BMD (chronic heparin, anticonvulsants, depot medroxyprogesterone acetate) 1
• Chronic conditions accelerating bone loss (chronic renal failure, rheumatoid arthritis, inflammatory bowel disease, eating disorders, malabsorption syndromes, organ transplantation) 1, 2
• Significant osteopenia plus additional risk factors 1

Special Population Guidelines

Female Athletes with Triad Risk Factors

Athletes with high-risk Female Athlete Triad factors require DXA testing every 1-2 years to determine ongoing bone loss and evaluate treatment effectiveness. 4 This includes athletes with:

• History of eating disorders or BMI <17.5 kg/m² 4
• Amenorrhea (<6 menses over 12 months) 4
• Prior stress fractures 4

Diabetes Patients

• Type 2 diabetes: Perform initial DXA at least 5 years after diagnosis, then reassess every 2-3 years depending on additional risk factors 4
• Type 1 diabetes: Consider BMD assessment after age 50, with repeat intervals based on risk factors 4
• Patients undergoing bariatric-metabolic surgery: Repeat DEXA every 2 years 4

HIV-Infected Patients

• Post-menopausal women and men ≥50 years with HIV: Initial DXA recommended 4
• If results don't warrant treatment: Repeat every 2-5 years depending on proximity to treatment thresholds 4

Critical Technical Considerations to Ensure Accuracy

Always perform follow-up scans on the same DXA machine to ensure accurate comparison between tests. 1, 3

Compare BMD values (g/cm²), not T-scores, between serial scans for more accurate assessment of changes. 1, 3

Be aware that degenerative changes can falsely elevate BMD values, particularly in the spine, potentially masking true bone loss. 3

Clinical Situations Requiring Immediate Repeat Testing

Regardless of scheduled intervals, repeat DEXA testing should be performed when:

• A fragility fracture has occurred 3
• New risk factors have developed (hyperparathyroidism, malabsorption, initiation of bone-depleting medications) 3
• Monitoring patients prior to temporary cessation of bisphosphonate therapy 3

Common Pitfalls to Avoid

Do not scan more frequently than annually unless there is a compelling clinical indication, as this wastes resources without providing actionable information. 1, 2

Do not ignore new risk factors that develop between scheduled scans—these warrant earlier follow-up regardless of the previous schedule. 3

Do not rely solely on spine measurements in elderly patients with degenerative changes, as osteoarthritis and other artifacts commonly cause spurious increases in BMD values. 3