Bone density is indicated by a T-score and the lower the T-score, the lower the bone density. A T-score of -1.0 or higher indicates a normal bone density, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases.
Bone mineral density tests are used to measure bone density and diagnose bone diseases, such as osteoporosis. The amount of bone in a patient's hip and spine is measured and the results are classified using a T-score. A T-score indicates the bone density compared to that of a 30 year old healthy adult. According to the National Osteoporosis Foundation, the baseline score is 0 and a score of -1.0 or above is considered normal. A score between -1.0 and -2.5 indicates low bone density or osteopenia and a T-score of -2.5 or lower reveals osteoporosis.
Bone density can also be given a Z-score, which is a score based on a comparison to the average score for a person of the patient's age. This score is usually considered only after the T-score has revealed bone loss and is used to help identify any conditions which may be causing the low bone density.
Once low bone density has been identified, there are steps which can be taken to slow the rate of bone loss. The National Institute of Arthritis and Musculoskeletal and Skin Diseases claims that healthy eating, exercise and medication can all help to prevent the development of osteoporosis.