What Is a Bone Mineral Density Test (BMD)?
A Bone Mineral Density test, also called bone densitometry, is used to diagnose osteoporosis. It measures and compares your bone density with standards for what is expected in someone of your age, gender, and size to the optimal peak bone density of a healthy young adult of the same gender. Such testing can help:
- Detect low bone density before a fracture occurs.
- Confirm a diagnosis of osteoporosis if you have already had a fracture.
- Predict your chances of a fracture in the future.
- Determine the rate of bone loss and monitor the effects of treatment when testing is done at regular intervals.
A BMD test is the most accurate method of measuring bone density, uses the least amount of radiation, and is less expensive than other methods.
What To Expect
You will be asked to lie on an examination table. Using a special machine, the technologist will measure the density at the hip and spine, since these are the areas where osteoporosis begins. During the exam, a beam of very low-dose x-rays will be passed through the area being studied. Then the amount of x-rays absorbed by the bone will be compared to the amount absorbed by soft body tissues that do not contain bone. This exam is painless.
- Eat as you normally do on the day of your exam.
- Do not take any calcium supplements for 24 hours before your exam.
- If you have had a radioisotope injection, a barium study, or received oral or intravenous contrast material during a CT scan or MRI, you must wait seven days before having a BMD.
- Wear loose, comfortable clothing, such as a sweat suit or other casual attire that does not have metal zippers or buttons.