Bone Density Test

What is a bone density test?

A bone density test is an imaging test that measures the strength of your bones. It uses X-rays to measure how much calcium and other minerals are in your bones.

Healthcare providers sometimes refer to bone density tests as DXA scans or bone density scans. These are different names that refer to the same test. “DXA” is an acronym for “dual-energy X-ray absorptiometry.”

When is a bone density test performed?

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

• Diagnose osteoporosis.
• Diagnose osteopenia.
• Check your risk of experiencing a bone fracture.

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.
• Checking how your bones respond to treatment for osteoporosis or osteopenia.
• Evaluating your bone density before you start a treatment or medication that can weaken your bones as a side effect.

Who needs a bone density test?

Anyone might need a bone density test if a healthcare provider wants to check your bones’ strength. Some people have a naturally higher risk of developing osteoporosis and other conditions that affect bone density, including:

• Women and people assigned female at birth (AFAB) older than 65.
• Men and people assigned male at birth (AMAB) older than 70.
• Anyone older than 50 who’s broken a bone.
• People whose biological parents or grandparents have osteoporosis.
• Anyone who’s lost an inch or more of height in the last year.
• People who have an autoimmune disorder.

Other risk factors for bone density issues include:

• Using tobacco.
• Alcohol use disorder.
• Vitamin D deficiency.
• Taking medications like corticosteroids, some types of cancer medication and immunosuppressants.

How is a bone density test done?

A bone density test uses low levels of X-rays to measure the density and mineral content of your bones. It’s similar to a typical X-ray.

It’s an outpatient procedure, which means you won’t have to stay in the hospital. And there aren’t any needles or injections in this test.

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 position your body. They might put foam blocks under or around you to hold you in the proper position.
• The technician will pass a scanning arm over your body that takes pictures of your bones.

How do I prepare for a bone density test?

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.
• If you take a calcium supplement or other over-the-counter vitamins, stop taking them 24 hours before your bone density test. Tell your provider which vitamins and supplements you’re taking before your test.
• 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.

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 scanned.

What does a bone density test show?

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 shadows in the background of the test images.

What are the risks of a bone density test?

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

Pregnant people shouldn’t have a bone density test. Medical experts recommend avoiding all radiation exposure during pregnancy to protect the developing fetus. Tell your provider if you’re pregnant or think you might be pregnant.

What type of results do you get from a bone density test and what do they mean?

The results of a bone density will show how strong 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 30-year-old. The results are measured as a negative number. The closer to zero your T score is, the stronger your bones are:

• -1 or higher is a healthy bone density.
• A score between -1.5 and -2.5 means you’re at risk for osteoporosis.
• -2.5 or lower means you have osteoporosis or weakened bones.

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 exercise strengthens your bones. Walking, swimming and yoga are great ways to exercise without putting extra stress on your bones.
• Supplements or diet changes: Adding a calcium or vitamin D supplement to your diet can support bone health. You can add foods higher in certain vitamins and minerals into your diet.
• Medication: Your provider might prescribe medications that help slow down bone loss.

When should I call my doctor?

Talk to a healthcare provider about a bone density test if you have a family history of osteoporosis.

Women and people AFAB should have regular bone density screenings starting at 65. Men and people AMAB at birth should have regular tests starting at age 70.

A note from Cleveland Clinic

A bone density test is a quick, painless way to check your bone health. Your healthcare provider might suggest one to screen for osteoporosis or to make sure your bones are as strong as they should be.

Women and people assigned female at birth and anyone with a family history of osteoporosis should have regular bone density screenings. Ask your provider how often you need your bone density checked.