IGF-I assays: current assay methodologies and their limitations
IGF-I assays: current assay methodologies and their limitations
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DOI：
10.1007/s11102-007-0032-z
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发表时间：
2007-06-01
期刊：
影响因子：
3.8
通讯作者：
Clemmons, David R.
中科院分区：
文献类型：
--
作者：
Clemmons, David R.
生长激素（GH）紊乱的诊断依赖于胰岛素样生长因子-I（IGF-I）浓度的准确测量，因为已发现血清IGF-I测定可用作儿童中生长激素缺乏症（GHD）存在的筛查试验，并且在儿童和成人中，已发现它们在建立肢端肥大症的诊断中非常有用。IGF-I还广泛用于监测儿童和成人对GH治疗的反应，以及监测肢端肥大症对治疗的反应。由于IGF-I受到其他几种激素和生理因素以及GH的影响，因此了解其调节对于理解如何正确解释测量结果至关重要。成功的IGF-I值的实验室估计需要几个技术标准。这些措施包括消除IGF-I结合蛋白（IGFBP）的干扰，利用足够数量的正常受试者来定义正常范围，重要的是使用高亲和力，高特异性抗血清，允许生物活性肽的精确和可重复的测量。各种商业测定的交叉比较表明，当值在正常范围内时，结果通常相似。然而，当浓度高于或低于正常范围时，检测试剂盒具有不同的性能特征。为了对超出正常范围的值进行跨实验室标准化，需要使用相似的高质量试剂和技术，这些试剂和技术具有合理的可比性。如果没有这种程度的标准化，不同参考实验室之间的交叉比较可能会继续显示出高于或低于95%置信区间的值的巨大差异。未来的目标应该是开发标准程序和试剂，消除这种程度的变异性。
The diagnosis of disorders of growth hormone (GH) is dependent upon accurate measurement of insulinlike growth factor-I (IGF-I) concentrations since serum IGF-I assays have been found to be useful as a screening tests for the presence of growth hormone deficiency (GHD) in children and in both children and adults they have been found very useful in establishing the diagnosis of acromegaly. IGF-I is also used extensively to monitor the response to GH treatment in children and adults and to monitor the response to treatment in acromegaly. Since IGF-I is influenced by several other hormones and physiologic factors as well as GH, a knowledge of its regulation is essential to understanding how to properly interpret the measurements. Several technical criteria are required for successful laboratory estimation of IGF-I values. These include elimination of interference of IGF-I-binding proteins (IGFBP), utilization of adequate numbers of normal subjects to define the normal ranges and importantly the use of high affinity, high specificity antisera that allow precise and reproducible measurements of the biologically active peptide. Cross comparisons of various commercial assays show that the results generally are similar when values are in the normal range. However, the assays have different performance characteristics when concentrations are either above or below the normal range. To obtain cross laboratory standardization for values outside the normal range requires utilization of similar, high-quality reagents and techniques that are reasonably comparable. Without this degree of standardization, cross comparisons among various reference laboratories are likely to continue to show wide divergence for values that are above or below the 95% confidence interval. A future goal should be the development of standard procedures and reagents that eliminate this degree of variability.