What is mean bone density?

Mean bone density is the average density (mass per unit of volume) of a bone. A bone mineral density (BMD) test is used to determine this value, according to the NYS Department of Health.

Dual X-ray absorption is used to measure the density of bone in the hip or spine, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases. The patient's mean bone density is then compared to the ideal bone density of a healthy adult to obtain a T-score, or to a typical adult of the same age to obtain a Z-score. These scores are used to diagnose low bone mass or osteoporosis.