When undergoing a bone density test, the patient usually lays on a table while a mechanical arm moves along the body similar to an X-ray, according to Mayo Clinic. There is a very low amount of radiation exposure during this test, and the test takes about 10 to 30 minutes.
Bone density tests are painless and easy for the patient, and there is no preparation necessary, explains Mayo Clinic. If the individual has recently had a barium exam, nuclear medicine test or computed tomography scan, it is important to inform the doctor ordering the test, as the contrast materials may interfere with the results.
There are no major risks associated with bone density scans, but there are some limitations of the test, warns Mayo Clinic. For instance, there are differences in testing methods from place to place. The tools that measure the density of the hip and spine bones are more accurate than devices that measure the bone density in the finger, forearm or heel bone. Another limitation is that insurance does not always cover the cost of the test, making it cost-prohibitive for some patients.
These tests also do not identify the cause of low bone density, adds Mayo Clinic. This test shows that a patient has low bone density, but it does not indicate why the density is low. To get more information, a doctor often does a complete examination.