How osteoporosis is diagnosed

Osteoporosis is diagnosed with a bone density test called a DEXA scan (dual-energy X-ray absorptiometry). This is a quick, painless X-ray that measures how much mineral is in your bones and compares it to a healthy young adult's bones. The scan takes about 10 to 30 minutes and uses very little radiation—less than a standard chest X-ray.

Your doctor orders a DEXA scan based on your age, sex, medical history, and risk factors. You don't need symptoms to get tested; osteoporosis often has no warning signs until a bone breaks. The test is the only way to know your bone density before a fracture happens.

After the scan, you receive a report with two numbers: your T-score and your Z-score. The T-score tells you whether you have normal bone density, low bone density (osteopenia), or osteoporosis. The Z-score compares your bones to others your age and sex, which helps your doctor spot unusual bone loss.

Key Takeaways

  • A DEXA scan is the standard test for bone density and takes 10 to 30 minutes with minimal radiation exposure.
  • Your T-score determines the diagnosis: -1.0 or higher is normal, between -1.0 and -2.5 is osteopenia, and -2.5 or lower is osteoporosis.
  • You may be tested even without symptoms because osteoporosis causes no pain or warning signs before a fracture occurs.
  • Your doctor uses your T-score, age, sex, and fracture risk to decide whether treatment is needed.

Who should be tested and when

The U.S. Preventive Services Task Force recommends bone density screening for all women age 65 and older, and for postmenopausal women under 65 who have risk factors. Men age 70 and older should also be screened. Younger people of any sex may be tested if they have conditions or medications that weaken bone, or a personal or family history of fractures.

Your doctor may recommend earlier testing if you have rheumatoid arthritis, chronic kidney disease, take corticosteroids long-term, have had a previous fracture, or have a parent or sibling with osteoporosis. Estrogen loss after menopause is a major risk factor for women, so screening often begins around age 50 to 65.

If your first scan shows normal bone density, you may not need another for 10 years. If you have osteopenia, your doctor will discuss whether repeat testing in one to two years makes sense. If you have osteoporosis or are being treated, your doctor may order follow-up scans every one to two years to see if treatment is working.

What your T-score means

The T-score is a number that compares your bone density to a healthy 30-year-old's. A T-score of -1.0 or higher means your bones are normal. A score between -1.0 and -2.5 means you have osteopenia, or low bone density—your bones are weaker than normal but not yet in the osteoporosis range. A score of -2.5 or lower means you have osteoporosis.

The lower your T-score, the weaker your bones and the higher your fracture risk. A T-score of -3.0 means your bones are significantly weaker than a healthy young adult's. However, the T-score alone does not determine whether you need treatment. Your doctor also considers your age, sex, other medical conditions, and your 10-year fracture risk using a tool called FRAX (Fracture Risk Assessment Tool).

FRAX combines your T-score with other factors—age, weight, smoking, alcohol use, corticosteroid use, and rheumatoid arthritis—to estimate your chance of a hip or major osteoporotic fracture in the next 10 years. This number helps your doctor decide whether medication is worth starting.

What happens during a DEXA scan

You lie on a padded table while a scanner arm passes over your spine, hip, and sometimes your forearm. You stay still for a few minutes while the machine takes images. You don't need to change clothes, remove jewelry, or fast beforehand. Tell the technician if you are pregnant or think you might be, or if you have had a recent CT scan with contrast dye, because contrast can interfere with results.

The scan is painless and you feel nothing during it. There is no injection, no dye, and no enclosed space—you are not in a tube. The radiation dose is so small that you can have the test done safely even if you have had other X-rays recently. After the scan, you can go about your day normally.

Results usually come back within a few days to a week. Your doctor will review them with you and explain what they mean for your health and whether any treatment or lifestyle changes are needed.

Other tests that may accompany bone density screening

Your doctor may order blood or urine tests alongside your DEXA scan to rule out other causes of bone loss. A blood test can check your vitamin D level, calcium, kidney function, and thyroid function—all of which affect bone health. Low vitamin D is common and is often treated with supplements before or alongside osteoporosis medication.

If you have had a fracture, your doctor may order additional imaging such as an X-ray or CT scan to see the break itself and rule out other problems. If your bone loss seems unusually fast or you are younger than expected for osteoporosis, your doctor may test for conditions like hyperparathyroidism or multiple myeloma.

When to get tested after a fracture

If you break a bone from a minor fall or accident, your doctor should order a DEXA scan to check your bone density. A fracture from a small fall—called a fragility fracture—is a sign that your bones may be weaker than expected for your age. Even if you have not been diagnosed with osteoporosis, a fragility fracture means you should be tested and likely treated.

Common fragility fractures are hip, spine, and wrist breaks from falling from standing height or less. If you break a bone and your doctor does not mention bone density testing, ask for it. Knowing your bone density after a fracture helps your doctor decide on treatment to prevent future breaks.

What happens if you are diagnosed with osteoporosis

A diagnosis of osteoporosis does not mean a fracture is inevitable. It means your bones are weaker than normal and your fracture risk is higher. Your doctor will discuss whether medication is right for you based on your T-score, age, sex, and FRAX score. Not everyone with osteoporosis needs medication—some people benefit more from vitamin D and calcium, exercise, and fall prevention.

If medication is recommended, common options include bisphosphonates (such as alendronate), which slow bone loss and are taken by mouth or injection. Your doctor will also likely recommend vitamin D and calcium supplements if your levels are low, weight-bearing exercise, and avoiding smoking and excess alcohol. You may have repeat DEXA scans in one to two years to see if treatment is slowing bone loss.

Frequently Asked Questions

Does a DEXA scan hurt?

No. A DEXA scan is painless. You lie on a table while a scanner arm passes over your bones. There is no injection, no enclosed space, and no sensation during the test. The entire scan takes 10 to 30 minutes.

Can I get a bone density test without a doctor's order?

In most cases, you need a doctor's order for a DEXA scan at a hospital or imaging center. Some pharmacies and health fairs offer screening scans, but these are less detailed and may not be covered by insurance. Talk to your doctor about whether testing is right for you.

What if my T-score is between -1 and -2.5?

This range is called osteopenia, or low bone density. You do not have osteoporosis yet, but your bones are weaker than normal. Your doctor will discuss whether you need medication or whether lifestyle changes like exercise, vitamin D, and calcium are enough. Repeat testing in one to two years may help track whether your bone density is stable or declining.

How often do I need a bone density test?

If your bones are normal, you may not need another scan for 10 years. If you have osteopenia, your doctor may recommend retesting in one to two years. If you have osteoporosis or are on treatment, your doctor may order scans every one to two years to monitor how well treatment is working.

Can osteoporosis be reversed?

Osteoporosis cannot be completely reversed, but treatment can slow bone loss and sometimes increase bone density slightly. The goal is to prevent fractures by stopping further bone loss and maintaining the bone you have. Starting treatment early and combining medication with exercise and good nutrition gives the best results.