WHAT IS A BONE MINERAL DENSITY (BMD) TEST?

Following a comprehensive medical assessment, your doctor may recommend that you have your bone mass measured. Bone mineral density (BMD) test measure bone density in the spine, hip, and/or forearm. These are the most common sites of fractures due to osteoporosis, a disorder in which bones gradually become thinner and weaker. Osteoporosis is often called the “silent killer” because the condition can often go undetected until it is severe and fractures begin to occur. Until the age of about 30, you build and store bone efficiently. Then, as part of the natural aging process, your bones begin to break down faster than new bone can be formed.

Being female
Being thin and/or having a small frame
Advanced age
A family history of osteoporosis
Estrogen deficiency as a result of menopause, especially early or surgically induced
Anorexia nervosa
Low lifetime calcium intake
Use of certain medications, such as corticosteroids and anitconvulsants
Low testosterone levels in men
An inactive lifestyle
Current cigarette smoking
Excessive use of alcohol
Being Caucasian or Asian, although African Americans and Hispanic Americans are at significant risk as well

WHY WOULD I NEED A BONE MINERAL DENSITY TEST

A bone density test can:

Detect osteoporosis before a fracture occurs
Predict your chances of fracturing in the future
Confirm a diagnosis of osteoporosis if you have already suffered a fracture.
Determine your rate of bone loss and/or monitor the effects of treatment if the test is conducted at intervals of a year or more.

HOW IS BONE MINERAL DENSITY MEASURED

Bone density is measured through painless, noninvasive scanning techniques based on X-ray radiation. These techniques require you to be positioned for the scan and hold still while it is being completed. Dual Energy X-ray Absorptiometry (DEXA) measures the spine, hip, and/or forearm, and is the most widely used technique available. The procedure exposes the patient to little radiation, needs little scanning time, is inexpensive and is highly accurate. Because of its precision, DEXA is well suited to making serial (repeated) measurements. Serial bone density measurements may be done to track bone loss over time, to evaluate the effectiveness of treatment, or as part of a clinical trial for a new potential treatment for osteoporosis.

HOW DO I PREPARE FOR THE EXAM?

Wear comfortable clothing with no metal zippers, buttons, or buckles. Let the technologist know if you are pregnant or think you may be. Also let the technologist know if you have had recent fractures, metal implants inside your body (hip replacements or back surgeries). It is also important to inform the technologist if you have had a recent nuclear medicine scan or a barium exam.

WHAT CAN I EXPECT DURING THE EXAM?

During a DEXA bone density scan, you will be asked to lie on a table on your back. The scanner arm will move back and forth over the part of your body being scanned. Typical DEXA exams are completely painless and only take 10-15 minutes to perform.

WHAT DO THE RESULTS MEAN?

Your bone density is compared to two standards, or norms, known as “age matched” and “young normal.” The age-matched reading compares your bone density to what is expected in someone of your age, sex, and size. The young normal reading compares your density to the optimal peak bone density of a healthy young adult of the same sex.

The information from a bone density test enables your doctor to identify where you stand within ranges of normal and to determine whether you are at risk for fractures. In general, the lower your bone density, the higher your risk for fractures. Test results will help you and your doctor decide the best course of action for your bone health.