15 Sep What Is a DEXA Scan?
A DEXA scan (Dual-Energy X-ray Absorptiometry) is the gold standard for measuring bone mineral density (BMD). It’s a quick, painless, and non-invasive test that helps detect osteopenia (low bone mass) or osteoporosis (fragile bones) before a fracture occurs.
Rheumatologists use DEXA scans to:
- Diagnose bone loss
- Assess fracture risk
- Monitor treatment effectiveness over time
📊 Key Numbers on Your DEXA Report
Your scan results will include two important scores: the T-score and the Z-score.
- T-Score
This compares your bone density to that of a healthy 30-year-old adult of the same sex.
| T-Score Range | What It Means |
| -1.0 or above | Normal bone density |
| Between -1.0 and -2.5 | Osteopenia (low bone mass) |
| -2.5 or lower | Osteoporosis |
Rheumatologists use the T-score to diagnose osteoporosis and determine if treatment is needed.
- Z-Score
This compares your bone density to others of your same age, sex, and body size.
- A Z-score above -2.0 is considered within the expected range for age.
- A Z-score below -2.0 may suggest an underlying cause of bone loss (e.g., medication, disease).
Z-scores are especially important in younger patients or men, where age-related bone loss is less expected.
🧠 How Rheumatologists Use These Scores
Rheumatologists don’t just look at the numbers — they interpret them in the context of your overall health, risk factors, and medical history. Here’s how they approach it:
- T-score ≤ -2.5? You likely meet the criteria for osteoporosis and may need medication.
- T-score between -1.0 and -2.5? You’re in the osteopenia range. Your doctor will assess fracture risk using tools like FRAX (Fracture Risk Assessment Tool).
- Z-score < -2.0? Your doctor may investigate secondary causes of bone loss, such as hormonal imbalances, chronic illness, or medication side effects.
🧮 Beyond the Numbers: Other Factors Considered
Rheumatologists also evaluate:
- History of fractures (especially from standing height)
- Family history of osteoporosis
- Use of corticosteroids or other bone-impacting medications
- Lifestyle factors (smoking, alcohol, physical activity)
- Calcium and vitamin D intake
- Menopausal status in women or testosterone levels in men
🔁 Monitoring Progress
If you’re on treatment for osteoporosis, your rheumatologist will likely repeat your DEXA scan every 1–2 years to:
- Track changes in bone density
- Evaluate how well your medication is working
- Adjust your treatment plan if needed
Even small improvements or stabilization in bone density can be a sign that treatment is effective.
📝 What to Ask at Your Appointment
When reviewing your DEXA scan with your rheumatologist, consider asking:
- What is my T-score and Z-score?
- Do I have osteopenia or osteoporosis?
- What is my risk of fracture?
- Should I start treatment or make lifestyle changes?
- When should I have my next scan?
Understanding your DEXA scan results is the first step toward stronger bones and a safer future. At Island Rheumatology, we’re here to help you interpret the numbers, understand your risk, and take action that protects your independence and quality of life.
