Learn About Preparing for Bone Density Tests

What Is a Bone Density Test and Why It Matters

A bone density test, also called a DXA scan or DEXA scan, measures how much mineral is packed into your bones. Think of it like measuring the strength and thickness of a brick wall—the denser the bricks, the stronger the wall. Your bones naturally contain calcium and other minerals that make them hard and strong. Over time, especially as you age, bones can lose some of these minerals and become weaker. A bone density test shows whether your bones are as strong as they should be for your age and sex.

According to the National Institutes of Health, about one in three women and one in five men over age 50 will break a bone due to low bone density, a condition called osteoporosis. Many people don't realize their bones are weakening until they break something from a minor fall or bump. The benefit of a bone density test is that it can detect bone weakness before a fracture happens, giving you time to take steps to strengthen your bones.

The test uses low-level X-rays to measure bone mineral density. The amount of radiation exposure is very small—much less than a chest X-ray. The test typically takes about 10 to 30 minutes and causes no pain. Doctors use the results to understand your risk of breaking bones in the future and to guide treatment decisions if needed.

Common reasons doctors recommend bone density tests include age over 65, personal or family history of fractures, use of certain medications like steroids, hormonal changes from menopause, and certain medical conditions that affect bone health. If you have concerns about your bone health, talking with your doctor about whether a test makes sense for you is a useful first step.

Practical takeaway: Understanding what a bone density test measures—the mineral content and strength of your bones—helps you know what to expect and why your doctor might recommend one.

Who Should Consider Getting a Bone Density Test

Different people have different levels of risk for bone weakness. The U.S. Preventive Services Task Force recommends bone density screening for women age 65 and older, and for younger women and men with risk factors. However, individual circumstances vary widely, and your doctor's recommendation should be based on your specific health situation.

Several groups of people commonly receive bone density tests. Women who have gone through menopause or are experiencing significant hormonal changes often benefit from testing, since estrogen helps maintain bone strength and drops sharply during menopause. Men over 70 may also be tested, since bone loss accelerates with age in men as well. People taking long-term corticosteroid medications—used for conditions like rheumatoid arthritis or chronic lung disease—tend to lose bone density faster and often receive tests. Individuals with a personal history of broken bones from minor falls, family members who had osteoporosis, or those with conditions affecting calcium absorption (like celiac disease or inflammatory bowel disease) are also common candidates.

People with certain medical conditions have higher-than-average risk. These include thyroid disorders, kidney or liver disease, diabetes, multiple myeloma, and rheumatoid arthritis. Additionally, lifestyle factors play a role. Smoking, heavy alcohol use, sedentary behavior, and inadequate calcium or vitamin D intake all contribute to weaker bones. Your doctor can review your personal and family health history, current medications, and lifestyle to determine whether a bone density test would provide useful information for your situation.

Some people may not need testing. For example, young adults with no risk factors typically have strong bones and don't need screening. However, if you have any concerns about your bone health, discussing this with your healthcare provider is valuable. They can help you understand your individual risk and whether testing would be worthwhile.

Practical takeaway: Knowing whether you fit into a higher-risk group for bone weakness helps you have an informed conversation with your doctor about whether a test might be appropriate for you.

How to Prepare for Your Bone Density Test Appointment

Preparing for a bone density test is straightforward, and there's minimal fuss involved compared to many other medical procedures. A few days before your appointment, you should stop taking calcium supplements, antacids containing calcium, and calcium-fortified foods in large quantities—but only if your doctor instructs you to do so. These substances can interfere with the test results by showing artificially high calcium levels. Most doctors recommend stopping these supplements at least 24 hours before the test, though some may ask for a longer period. This doesn't mean avoiding calcium-containing foods like milk or cheese; it means pausing supplemental calcium products.

On the day of your test, wear loose, comfortable clothing without metal. Metal zippers, buckles, underwire bras, or jewelry can interfere with the X-ray images. Many facilities ask that you remove all metal objects from your body before the scan. If you're unsure what to wear, calling the facility ahead of time to ask what clothing works best can save time during your appointment.

Bring any important documents your healthcare provider's office requested. This typically includes your insurance card and photo identification. If you have a list of medications and supplements you take, bringing this can be helpful, as certain medicines affect bone density. Tell the technician if you've had any recent X-rays, CT scans, or nuclear medicine scans, since these might affect the interpretation of your bone density test.

There are few physical restrictions before or after the test. You can eat and drink normally, take your regular medications, and return to daily activities immediately after. No special diet is needed beforehand. If you take medications other than calcium supplements, continue taking them on schedule unless your doctor says otherwise. If you have any questions or unusual circumstances—such as being pregnant, recently having a fracture in the area being tested, or having metal implants—mention these to the facility when scheduling.

Practical takeaway: Simple steps like stopping calcium supplements a day or two before the test, wearing metal-free clothing, and bringing your insurance information ensure the test goes smoothly and produces accurate results.

What to Expect During the Bone Density Test

When you arrive for your bone density test, you'll check in and may be asked to complete a brief health questionnaire about your medical history, medications, and risk factors for bone loss. A technician will explain the procedure and answer any questions before you begin. The whole appointment typically lasts 30 minutes to an hour, though the actual scanning time is usually just 10 to 30 minutes.

For the most common type of bone density test—the DXA scan—you'll lie on a padded examination table fully clothed. The machine has an arm that moves slowly over your body, most commonly scanning your lower spine, hip, and sometimes your forearm. You need to remain still during each scan, which usually lasts only a few minutes. The technician will position you and may place pillows under your knees or use straps to help keep you in the right position. The machine makes no noise and causes no pain. You won't feel anything during the scan.

Different bones may be scanned depending on your situation. The hip and spine are the most common areas tested because fractures in these locations are particularly serious in older adults. Some facilities also scan the forearm or heel. The technician may ask you to hold your breath for a few seconds while each area is being scanned to reduce motion. They'll likely step out of the room or stand behind a protective barrier while the X-rays are taken, which is standard safety practice.

After the scan is complete, you're done. No recovery time is needed. You can immediately return to your regular activities, eat, drink, and take medications normally. The images go to a doctor called a radiologist, who analyzes them and creates a detailed report. Your regular doctor will typically receive this report within a few days and will discuss the results with you at a follow-up appointment or phone call.

Practical takeaway: Knowing that the test is painless, quick, and requires only lying still for a few minutes helps reduce any anxiety about the procedure itself.

Understanding Your Bone Density Test Results

Bone density test results are reported using a measurement called a T-score, which compares your bone density to that of a healthy young adult. The T-score tells you how your bones measure up. A T-score of -1.0 or higher is considered normal bone density. A T-score between -1.0 and -2.5 indicates low bone density, a condition called osteopenia. A T-score of -