A bone density test is a medical imaging test that measures the mineral content and density of bones. It is a non-invasive test that can help to diagnose and monitor conditions that affect bone health, such as osteoporosis.
There are several different types of bone density tests, including DEXA (dual-energy X-ray absorptiometry) scans, which are the most commonly used. Other tests include ultrasound and quantitative CT scans.
During a DEXA scan, the patient lies on a table while a machine passes over the body, emitting low-dose X-rays that are absorbed by the bones. The amount of radiation used is very small, equivalent to a few days of natural background radiation. The test typically takes between 10 and 30 minutes to complete and is painless.
The results of a bone density test are reported as a T-score, which compares the patient's bone density to that of a young adult of the same sex. A T-score of -1.0 or higher is considered normal, while a T-score between -1.0 and -2.5 indicates low bone mass, and a T-score of -2.5 or lower is indicative of osteoporosis.
Bone density tests can be useful in diagnosing and monitoring conditions that affect bone health, such as osteoporosis, and assessing the risk of fractures in people with low bone mass. The tests are generally safe, although they are not recommended for pregnant women, as the radiation can be harmful to the developing fetus. Patients should talk to their healthcare provider about whether a bone density test is right for them and if so, how often they should have it.