What is a Bone Mineral Density Test?
A bone mineral density test is an easy reliable test that measures the density, or thickness, of your bones. It measures the amount of mineral (calcium) in a specific area of bone. The more mineral you have in the bone measured, the greater your bone density or bone mass.
A BMD test can:
- Measure the density of your bones
- Detect osteoporosis before a fracture occurs
- Help to predict your chances of fracturing in the future
- Monitor the effectiveness of treatments for osteoporosis
What is it like to have a BMD test and is it safe? 
The most standardized method to measure bone density is called dual x-ray absorptiometry (DXA) of the hip and spine. It is a quick and easy test. It is not necessary to undress as long as you have no buttons, zippers, or snaps on your clothing from your chest to thigh.
You simply lie on a table while a fast, painless low-dose x-ray is taken. Nothing is injected or swallowed. The radiation is so low that no protective shields are necessary for the patient or the x-ray technologist. In fact, the radiation approximates the background radiation you receive flying in an airplane from New York to California. That is only 10% of the radiation exposure of a chest x-ray.