Part 2: How Osteoporosis Is Diagnosed — Understanding Bone Density Tests and Fracture Risk

One of the most confusing parts of osteoporosis is the testing. Patients often tell me, “I don’t understand my bone density scan,” or “My numbers don’t sound that bad.” Let’s clear that up.

The DEXA Scan: Your Bone “Report Card”

The most common test used to diagnose osteoporosis is the DEXA scan (Dual-Energy X-ray Absorptiometry). It is:

• Painless

• Low-radiation

• Quick (about 10 minutes)

It usually measures bone density at:

• Hip

• Spine

• Sometimes forearm

What Is a T-Score?

Your DEXA results are reported as a T-score, which compares your bone density to a healthy 30-year-old adult.

• Normal: T-score –1.0 or higher

• Osteopenia (low bone mass): –1.0 to –2.5

• Osteoporosis: –2.5 or lower

A lower number means weaker bones and higher fracture risk.

Osteopenia vs Osteoporosis

Osteopenia is not osteoporosis, but it is a warning sign. Many fractures occur in people with osteopenia—especially if other risk factors exist. That’s why we look beyond just the T-score.

Osteopenia is the beginning phase to progressing towards Osteoporosis. Modifiable risk factors can be taken to reduce the progression towards Osteoporosis.

Fracture Risk Matters More Than a Single Number

As rheumatologists, we assess overall fracture risk, not just bone density. We consider:

• Age

• Prior fractures

• Steroid use

• Family history

• Balance and fall risk

A common tool we use is FRAX, which estimates your 10-year fracture risk. This helps determine who benefits from medication—even if bone density shows only osteopenia.

Symptoms You Should Not Ignore

Osteoporosis itself is silent, but fractures are not. Watch for:

• Sudden back pain without injury

• Loss of height

• Stooped posture

• A fracture after a minor fall

Spine fractures can occur without dramatic trauma and are often mistaken for muscle pain.

When Should You Be Tested?

In general:

• Women age 65+

• Men age 70+

• Younger adults with risk factors

• Anyone with a fragility fracture

• Patients with Autoimmune diseases

• Chronic use of corticosteroids.

Early testing saves bones—and independence.

Key Takeaway from Part 2

Bone density tests help us predict fractures before they happen. In Part 3, we’ll cover how osteoporosis is treated—and what you can do every day to protect your bones.