The three manufacturers of DEXA equipment do not give STANDARDIZED RESULTS. The differences are clinically important, making it difficult to compare a measurement made from one machine to the other. For example, the hip bone density on a Lunar scan is about 6% higher than on a Hologic scan. If the physician must try to compare studies done on different machines, the best way is to apply the following equations:
These are the equations:
sBMD = 1000 (a + b x BMD)
|Manufacturer||Parameter||Femoral neck||Trochanter||Total hip|
Using these equations, the average error using standarized BMD for an individual patient was 3.5%. Reference: Hui, SL, et al. Universal Standardization of Bone Density Measurements: A Method with Optimal Properties for Calibration Among Several Instruments. J Bone Mineral Research 1997;12:1463-70.