Mazess R B, Witt R
AJR Am J Roentgenol. 1983 Oct;141(4):789-91. doi: 10.2214/ajr.141.4.789.
Measurements of bone mineral content (BMC) were made in 14 different laboratories in the U.S. and four in Europe using commercially produced instrumentation (Norland Bone Mineral Analyzer) for 125I absorptiometry. A three-chambered standard (dipotassium hydrogen phosphate) was measured in each laboratory following their own calibration. The values of BMC in the middle range (0.6 g/cm) all were adequate (within +/- 2%), but the BMC values were underestimated by 5% or more in five laboratories for the largest chamber and in three laboratories for the smallest chamber. Width values were accurate (+/- 3%) over 0.7-1.6 cm. The effect of underestimating large values in clinical studies is to reduce the difference between normals and abnormals. Calibration error also may be responsible for the variable normal values found in the U.S. and Europe by some users of this instrument.
美国14个不同实验室和欧洲4个实验室使用商用仪器（诺兰德骨矿物质分析仪）进行125I吸收法测量骨矿物质含量（BMC）。每个实验室在自行校准后测量三室标准品（磷酸氢二钾）。中等范围（0.6 g/cm）的BMC值均足够（在+/- 2%以内），但五个实验室对最大腔室的BMC值低估了5%或更多，三个实验室对最小腔室的BMC值也低估了5%或更多。宽度值在0.7 - 1.6 cm范围内准确（+/- 3%）。在临床研究中低估大值的影响是减少正常人与异常人之间的差异。校准误差也可能是该仪器的一些美国和欧洲用户发现正常数值存在差异的原因。
