DXA Scan (Bone Density Test)

What is a DXA scan?

A DXA scan is an imaging test that measures the strength of your bones. It uses X-rays to measure your bone density. DXA is an abbreviation for dual-energy X-ray absorptiometry.

Healthcare providers sometimes refer to DXA scans as bone density scans, DXA scans or bone density tests. All of these are different names that refer to the same test. They used to be known as DEXA scans or DEXA tests, but healthcare providers don’t use that term anymore.

What is a DXA scan used to diagnose?

A healthcare provider might use a DXA scan to check your bones in a few situations, including to:

• Diagnose osteoporosis.
• Diagnose osteopenia.
• Check your bone fracture risk.

Your provider might use a bone density test to see how your bones have changed over time, including:

• Measuring the natural amount of bone loss that happens as you age and tracking your bone loss over time.
• Evaluating your bone density before you start a treatment or medication that can weaken your bones as a side effect.
• Checking if your bones are responding to treatment for osteoporosis or osteopenia.

When will I need a DXA scan?

Anyone might need their bone density checked with a DXA scan. Your healthcare provider will suggest one if they want to check your bone density and fracture risk.

Some people have a naturally higher risk of developing osteoporosis and other conditions that affect their bone density. Groups who need regular DXA scans include people:

• Assigned female at birth (AFAB) older than 65.
• Assigned male at birth (AMAB) older than 70.
• Older than 50 who’ve broken a bone in the past.
• Whose biological parents or grandparents have osteoporosis.
• Who’ve lost an inch and a half or more of height from their tallest height (usually when you’re in your 20s).

People younger than the ages above who have an increased risk of bone loss may need regular DXA scans, too. Your provider will tell you when (and how often) you should get your bone density checked.

Some health conditions or certain medications can increase your risk for bone density issues, including:

• Some autoimmune diseases.
• Smoking or using other tobacco products.
• Alcohol use disorder or drinking more than three servings of alcohol per day.
• Vitamin D deficiency.
• Corticosteroids.
• Some types of cancer medication.
• Certain immunosuppressants.
• Hormone suppressants.
• Some types of seizure medications.
• Proton pump inhibitors (PPIs) that treat acid reflux and GERD.
• Heparin (a blood thinner).

How is a bone density test done?

A bone density scan uses low levels of X-rays to measure the density and mineral content of your bones. It’s similar to a typical X-ray. That’s what the X in DXA stands for.

DXA scans are outpatient procedures, which means you won’t have to stay in the hospital. There are no needles or injections in this test, and you won’t feel any pain.

You might be able to wear your regular clothes during the test, or you may have to change into a hospital gown.

Here’s how a bone density scan works:

• You’ll lie on a special X-ray table.
• A technician (a radiologic technologist) will help you position your body. They might put foam blocks under or around you to hold your legs in the proper position.
• The technician will pass a scanning arm over your body that takes pictures of your bones. Technicians usually scan your hips and spine, but they may take scans of other bones throughout your body, too, like your forearms.

A bone density scanner uses two types of low-level radiation to translate your bone density into pictures and graphs on a computer. Your bones will show up as white. Fat, muscles and other soft tissue will look like dark shadows in the background of the test images.

What should you not do before a DXA scan?

You probably won’t have to change your usual routine before having a bone density test. In general, you can:

• Eat and drink before your test.
• Take all your usual medications, unless your provider asks you not to.
• Wear comfortable, loose-fitting clothing to your test. Try to wear items that don’t have metal (zippers, buttons or buckles). You’ll have to remove clothing and jewelry that contains metal before the test.

If you take a calcium supplement or other over-the-counter (OTC) vitamins, don’t take them 24 hours before your test. Tell your provider which vitamins and supplements you take. They’ll let you know which ones you can or can’t take before a DXA scan.

You won’t be able to have a DXA scan within 24 hours of certain other kinds of imaging tests. Tell your scheduler when you’re having other tests before you make your DXA scan appointment.

How long does a bone density test take?

A bone density test usually lasts around 30 minutes. Your test might be slightly shorter or longer depending on how many of your bones need scanning.

What are the disadvantages of a DXA scan?

There are very few risks to having a bone density test. You won’t feel any pain or have any side effects after the scan.

Pregnant people shouldn’t have a bone density test. Tell your provider if you’re pregnant or think you might be pregnant. DXA scans use such a low level of radiation that they’re harmless for almost everyone, but pregnant people should avoid all forms of radiation if possible.

Some studies have found that results and readings from DXA scans can vary between manufacturers of the scanning machines, but that’s not usually something you need to worry about. Your provider will monitor changes in your bone density over time and will suggest repeated or different tests if needed.

What type of results do you get from a DXA scan and what do they mean?

The results of a DXA scan will show how dense your bones are.

Healthcare providers use a system called a “T score” to measure your bone density. Your T score compares your bone density to a healthy, average person in their 20s or 30s. The results are measured as a negative number. The closer to zero your T score is (including being a positive number), the stronger your bones are:

• Between 0 and -1 is a healthy bone density.
• A score between -1 and -2.5 means you have osteopenia, which can increase your osteoporosis risk.
• -2.5 or lower means you have osteoporosis or weakened bones. It also means you have an increased risk of breaking a bone.

Your provider will discuss the results with you and explain what they mean. If you have a lower-than-usual bone density, your provider will suggest treatments to help keep your bones strong, including:

• Exercising more often: Regular physical activity strengthens your bones. Walking, yoga and strength training are great ways to stay active and prevent bone loss.
• Supplements or eating specific foods: Your provider might suggest that you take a vitamin D or calcium supplement to support your bone health. You might need to eat more foods high in certain vitamins and minerals.
• Medication: Your provider might prescribe medications that help slow down bone loss and prevent fractures. Some medications for osteoporosis may help build your bone density.

What is the difference between a DXA scan and a whole-body bone scan?

DXA scans and whole-body bone scans are similar tests. Both tests involve scanning your bones, but providers use them to check different aspects of your bone health.

DXA scans are special X-rays that measure your bone density to screen you for osteoporosis and other conditions that weaken your bones.

A whole-body bone scan lets providers check to see if a cancer you might have has spread (metastasized) to your bones. You might also need a whole-body bone scan to see which cancer stage you have. They can also detect infections, lesions and other issues.

A note from Cleveland Clinic

A DXA, DEXA or bone density scan. No matter what your provider calls it, this is a quick, easy (and painless) test. It’ll help your provider catch conditions that affect your bone density as soon as possible. You may need regular bone density screenings based on your age, family history or other risk factors you might have.

Everyone should have their bone density checked as they age. Ask your provider how often you need a DXA scan. Anyone with a family history of osteoporosis will need bone density screenings more often. Your provider will help you maintain your bone health to make sure your bones are strong enough to support you throughout your life.