A bone density test determines if you have osteoporosis — a disease that causes bones to become more fragile and more likely to break.
In the past, osteoporosis could be detected only after you broke a bone. By that time, however, your bones could be quite weak. A bone density test enhances the accuracy of calculating your risk of breaking bones.
A bone density test uses X-rays to measure how many grams of calcium and other bone minerals are packed into a segment of bone. The bones that are most commonly tested are in the spine, hip and forearm.
Why it’s done?
Doctors use bone density testing to:
- Identify decreases in bone density before you break a bone
- Determine your risk of broken bones (fractures)
- Confirm a diagnosis of osteoporosis
- Monitor osteoporosis treatment
The higher your bone mineral content, the denser your bones are. And the denser your bones, the stronger they generally are and the less likely they are to break.
Bone density tests differ from bone scans. Bone scans require an injection beforehand and are usually used to detect fractures, cancer, infections and other abnormalities in the bone.
Although osteoporosis is more common in older women, men also can develop the condition. Regardless of your sex or age, your doctor may recommend a bone density test if you’ve:
- Lost Height. People who have lost at least 1.6 inches (4 centimeters) in height may have compression fractures in their spines, for which osteoporosis is one of the main causes.
- Fractured a Bone. Fragility fractures occur when a bone becomes so fragile that it breaks much more easily than expected. Fragility fractures can sometimes be caused by a strong cough or sneeze.
- Taken Certain Drugs. Long-term use of steroid medications, such as prednisone, interferes with the bone-rebuilding process — which can lead to osteoporosis.
- Received a Transplant. People who have received an organ or bone marrow transplant are at higher risk of osteoporosis, partly because anti-rejection drugs also interfere with the bone-rebuilding process.
- Had a Drop in Hormone Levels. In addition to the natural drop in hormones that occurs after menopause, women’s estrogen may also drop during certain cancer treatments. Some treatments for prostate cancer reduce testosterone levels in men. Lowered sex hormone levels weaken bone.