Long-term reproducibility of bone mineral content measurements.

The long-term reproducibility of bone mineral content (BMC) measurements using two identical equipments for two-dimensional fore-arm scanning, was measured in normal persons and aluminium standards (corresponding to normal persons and severely osteopenic patients). The mean coefficient of variation in normal subjects measured for one year was 1.4%. The data were used to estimate that this equipment can measure BMC in osteopenic patients with a long term reproducibility of 1.7%, which is sufficient for use in the clinically relevant range of calcium balance.