A bone mass chart shows a healthy 30-year-old adult's peak bone mineral density, according to the National Institutes of Health Osteoporosis and Related Bone Diseases. Doctors compare patient T-scores to the chart to measure bone mass. T-scores between +1 and -1 are in the normal range for bone mineral density.
The bone mineral density test identifies osteoporosis, fracture risk and osteoporosis treatment response, explains the National Institutes of Health Osteoporosis and Related Bone Diseases. Doctors report bone mineral density test results as T-scores. On the bone mass chart, a T-score between -1 and -2.5 signifies low bone mass or osteopenia, and a T-score of -2.5 or lower signifies osteoporosis. The more severe the osteoporosis, the greater the negative number.