How to Prepare for a DEXA Scan: What You Need to Know
A DEXA scan (dual-energy X-ray absorptiometry) is a common screening tool used to measure bone mineral density and assess osteoporosis risk. If your doctor has scheduled one for you, preparation is straightforward—but knowing what to expect and what to do beforehand helps you get the most accurate results and have a smooth experience. 📋
What Happens During a DEXA Scan
A DEXA scan is a quick, painless imaging test that measures how dense your bones are. You lie on a padded table while a scanner passes over your body, taking pictures of your hip, spine, and sometimes your forearm. The entire process typically takes 10–30 minutes, and the radiation exposure is minimal—much lower than a standard chest X-ray.
The scan produces a T-score, which compares your bone density to that of a healthy young adult. This number helps your doctor understand your fracture risk and whether treatment might be needed.
Pre-Scan Preparation: The Essentials
What you should do:
- Wear comfortable, metal-free clothing. Remove jewelry, belts, and anything with zippers or snaps before the scan. Some facilities provide a gown; others let you keep your clothes on if they're clear of metal.
- Arrive on time. Check in a few minutes early to complete any paperwork.
- Bring your insurance card and photo ID. Have your doctor's referral if required by your facility.
- Tell the technician about any recent procedures or implants. If you've had barium studies, CT scans with contrast, or bone scans recently, mention this—they can affect results. Also disclose metal implants (hip replacements, pacemakers, etc.), though most don't prevent a DEXA scan.
What you don't need to do:
You don't need to fast, avoid medications, or change your routine before a DEXA scan. Take your regular medicines as scheduled. There's no special diet or preparation required.
Timing and Scheduling Considerations
The best time to schedule your scan depends on a few factors:
- After recent fractures heal. If you've had a break, wait until the bone has begun mending (usually several weeks) so the healing process doesn't skew results.
- Consistency matters for follow-ups. If this is a repeat scan to monitor changes over time, try to schedule it at roughly the same time of year as your previous one. Seasonal factors and medication changes can subtly affect measurements.
- Avoid immediately after contrast studies. If you had a barium X-ray or CT scan with contrast, wait a few days before your DEXA scan.
What Affects DEXA Scan Accuracy
Several factors can influence the reliability of your results:
| Factor | Impact |
|---|---|
| Recent weight loss or gain | Can affect bone density readings; stable weight for several weeks is ideal |
| Calcium and vitamin D levels | Don't directly show up on the scan, but low levels affect bone quality over time |
| Medications | Some drugs (like steroids) affect bone density; tell your doctor what you take |
| Osteoarthritis or spine fusion | Can artificially raise spine density scores; your doctor accounts for this |
| Metal implants | Usually don't prevent scanning but may create image artifacts in that area |
After Your Scan
Results typically arrive within a few days to a week. Your doctor will interpret them and discuss any next steps—whether that's lifestyle changes, follow-up testing, or treatment options. Don't assume results are "good" or "bad" on your own; context matters. The same T-score means different things depending on your age, sex, and medical history.
If you're scheduled for a follow-up DEXA scan in the future, ask your facility if they can use the same machine and positioning. Consistency helps track real changes in bone density rather than variations from equipment differences.
The main takeaway: DEXA scan preparation is minimal because the test itself is simple and safe. Focus on practicalities—comfortable clothing, arriving on time, disclosing relevant medical history—and let your technician handle the rest. Your doctor will help you understand what your results mean for your individual health picture.
