Key Takeaways:
• Gold Standard: DEXA is the only method to accurately diagnose osteoporosis before a fracture occurs.
• Who Needs It: All women over 65, men over 70, and anyone over 50 with a history of broken bones.
• Frequency: Scans are typically repeated every 2–5 years; more frequent scanning (e.g., annually) is rarely useful due to slow bone turnover.
• Preparation: The scan is painless and takes 15 minutes. Avoid calcium supplements for 24 hours prior.
Who Should Have a DEXA Scan?
You should have a DEXA scan if you are a woman aged 65+ or a man aged 70+, regardless of your health. Younger individuals (50+) should also be scanned if they have specific risk factors like a recent fracture, long-term steroid use, or a family history of hip fractures.
Osteoporosis is often called a “silent disease” because you cannot feel your bones getting weaker. A DEXA (Dual-energy X-ray Absorptiometry) scan is the medical equivalent of checking the fuel gauge before the car stops; it tells us your status before a crisis occurs.
Why Do Doctors Rely on DEXA Scores?
Unlike a standard X-ray, which only shows broken bones, a DEXA scan measures the actual mineral content of your bone tissue. It produces two critical numbers:
- T-Score: Compares your bone density to a healthy 30-year-old. This is used to diagnose osteoporosis in older adults.
- Z-Score: Compares you to someone of your own age and size. This is crucial for patients under 50 to identify “secondary” causes like malnutrition or hormonal issues.
How Often Should You Repeat a Scan?
We often see patients asking for scans every 6 months, but bone remodeling is a slow biological process. Significant changes rarely show up that quickly.
| Patient Status | Recommended Frequency |
|---|---|
| On Treatment | Every 1–2 years (to check efficacy) |
| Osteopenia (Untreated) | Every 2–5 years (monitoring) |
| Normal Bone Density | Every 5–10 years |
| High Risk (Steroids) | Every 1 year (specialist discretion) |
What Happens During the Appointment?
A DEXA scan is one of the easiest medical tests you will ever undergo. It is:
- Painless: You lie flat on an open table.
- Fast: The scan takes 10–15 minutes.
- Safe: The radiation dose is extremely low (less than a trans-Atlantic flight).
Preparation Checklist
- Clothing: Wear loose, comfortable clothes without metal zips or buttons.
- Supplements: Stop taking calcium supplements 24 hours before your scan (they can show up on the image and skew results).
- Food: You can eat normally on the day of the scan.
When Is a DEXA Scan NOT Appropriate?
While safe, DEXA is not for everyone. You should avoid it if:
- You are pregnant: Even low radiation is avoided.
- Recent Contrast Exams: If you’ve had a Barium meal or CT contrast in the last week, wait 14 days before your DEXA.
- Severe Arthritis: In some cases, spinal arthritis can artificially “boost” the bone density score. Our consultants are trained to spot this anomaly.
Conclusion: Don’t Guess, Test
Your bone health is the foundation of your future independence. If you meet the criteria, a DEXA scan is the single most effective step you can take today to prevent a fracture tomorrow.
Medically Reviewed by: Dr. Taher Mahmud, Consultant Rheumatologist
