Bone Density Test (DEXA): Diagnosis and Results

What Is a Bone Density Test (DEXA)?

A DEXA scan stands for dual-energy X-ray absorptiometry. It uses a low-dose X-ray to measure bone mineral density (BMD).

Bone minerals give bones their strength. The higher the density, the stronger the bone. DEXA is the most accurate test to detect bone loss and is considered the gold standard for diagnosing bone conditions.

When Is a Bone Density Test Recommended?

Doctors recommend a DEXA scan for people who are at risk of weak bones or fractures. You may need this test if you are:

• A woman aged 65 or older
• A postmenopausal woman with a prior fracture or risk factors
• A man aged 70 or older
• A man under 70 with a history of fractures or other risk factors

Other common reasons include long-term use of steroids, certain cancer treatments, or chronic diseases that affect bone strength.

How Is the DEXA Test Performed?

The DEXA test is simple and takes only a few minutes. It’s noninvasive and painless.

Here’s what happens:

• You lie flat on a padded table.
• A scanning arm moves over your body without touching you.
• It measures how much mineral is in specific bones, usually your hip and spine.
• The scan creates a T-score, which tells your doctor how your bone density compares to a healthy young adult.

You can return to your normal activities right after the test.

Important note: Try to use the same scanner for follow-up tests. This ensures more accurate comparisons over time

What Do DEXA Test Results Mean?

The test gives a T-score, which helps classify your bone density:

• 0 to -1: Normal bone density
• -1 to -2.49: Low bone mass (osteopenia)
• -2.5 or lower: Osteoporosis

A lower score means lower bone strength and a higher risk of fractures. Your doctor will review the results and recommend a treatment plan if needed.

Why Is Bone Density Important?

Bone density affects how strong and resistant your bones are to breaking. As we age, bones naturally lose density. If the loss is severe, bones can become fragile and break easily, even from a minor fall.

Low bone density often has no symptoms until a fracture occurs. That’s why early testing is important.

What Can Affect Bone Density?

Several factors can cause bone loss or increase your risk for conditions like osteopenia and osteoporosis. These include:

• Age (especially after menopause for women)
• Gender (women are more at risk)
• Family history of osteoporosis
• Small or thin body frame
• Low calcium or vitamin D intake
• Lack of physical activity
• Smoking
• Heavy alcohol use
• Medications such as steroids, hormone therapy for cancer, or seizure drugs
• Chronic conditions like diabetes or rheumatoid arthritis

Knowing your risk factors can help you take action early.

How to Improve or Maintain Bone Density

There are several proven ways to strengthen your bones:

• Eat a diet rich in calcium (e.g., dairy, leafy greens)
• Get enough vitamin D from sunlight or supplements
• Do weight-bearing exercises, like walking or strength training
• Avoid smoking and limit alcohol
• Manage conditions that affect bone health

These steps can slow bone loss and reduce your risk of fractures.

How Often Should You Get a DEXA Scan?

Most people don’t need the test more than every two years. However, if you have:

• Rapid bone loss
• A fracture
• A high-risk medical condition
• Ongoing treatment for osteoporosis

Your doctor may recommend more frequent testing.

Limitations and Considerations

• Radiation exposure from a DEXA scan is very low.
• The test shows bone density but not bone quality or structure, so it can’t diagnose conditions like cancer.
• It’s important to keep using the same scanner for follow-up tests.

Despite its limits, it remains the best available tool for monitoring bone health over time.

Which Doctor Should You See for a DEXA Test?

Start with your primary care doctor. They will evaluate your risk and refer you if needed. Depending on your situation, you may be referred to:

• An endocrinologist (for hormonal causes)
• A rheumatologist (for inflammatory diseases)
• A gynecologist (especially for postmenopausal women)

Some centers also offer pediatric DEXA scans for children as young as 5.