Determination of osteocalcin in human serum: results with two kits compared with those by a well-characterized assay.
Determination of osteocalcin in human serum: results with two kits compared with those by a well-characterized assay.
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人血清中骨钙素的测定：两种试剂盒的结果与充分表征的测定结果的比较。
作者：
C. Gundberg;P. Wilson;P. Gallop;A. Parfitt
骨钙素是骨骼中维生素 K 依赖性蛋白质，也可以在血清中检测到，并且作为评估代谢性骨病患者的骨转换标志物而受到越来越多的关注。我们比较了两种商业放射免疫测定试剂盒（Immuno Nuclear Corp. 和 Seragen Inc.）和我们内部放射免疫测定（Methods Enzymol 107: 517, 1984）测定的患者结果。我们的测定结果与两种试剂盒的结果相关性良好（r 大于 0.9），但免疫核法和 Seragen 方法的值分别比我们的放射免疫测定法低 40% 和 10%。两种试剂盒方法的运行内变异 (CV) 分别为 7.3% 和 9.8%，运行间 CV 分别为 9.7% 和 8.6%。对于免疫核试剂盒，标准曲线在 1 至 25 微克/L 范围内呈线性；对于 Seragen 平衡方法，标准曲线在 4 至 100 微克/L 范围内呈线性；对于 Seragen 非平衡方法，标准曲线在 1 至 25 微克/L 范围内呈线性。对于两种试剂盒方法，第二次冻融循环使血清值降低了 20% 至 40%。第三次冻融循环进一步降低了数值并消除了方法之间的任何相关性。
Osteocalcin, the vitamin K-dependent protein in bone, can also be detected in serum and is receiving increased attention as a marker for bone turnover in evaluating patients with metabolic bone disease. We compared results for patients as determined with two commercial radioimmunoassay kits (Immuno Nuclear Corp. and Seragen Inc.) and with our in-house radioimmunoassay (Methods Enzymol 107: 517, 1984). Results by our assay correlated well (r greater than 0.9) with those by both kits, but the values by the Immuno Nuclear and Seragen methods were respectively 40% and 10% lower than by our radioimmunoassay. Within-run variation (CV) for the two kit methods was respectively 7.3% and 9.8%, run-to-run CV was 9.7% and 8.6%. The standard curve was linear from 1 to 25 micrograms/L for the Immuno Nuclear kit, from 4 to 100 micrograms/L for the Seragen equilibrium method, and from 1 to 25 micrograms/L for the Seragen nonequilibrium method. A second freeze-thaw cycle reduced the serum values by 20% to 40% for both kit methods. A third freeze-thaw cycle further reduced values and eliminated any correlation among methods.