Service d'Endocrinologie et des Maladies de la Reproduction and Centre de Référence des Maladies Rares de l'Hypophyse, F94275 Le Kremlin-Bicêtre, France.
Inserm 1185, Fac Med Paris Sud, Université Paris-Saclay, F94276 Le Kremlin-Bicêtre, France.
J Clin Endocrinol Metab. 2017 Aug 1;102(8):2844-2852. doi: 10.1210/jc.2017-00202.
Insulinlike growth factor I (IGF-I) measurement is essential for the diagnosis and management of growth hormone (GH) disorders. However, patient classification may vary substantially according to the assay technique.
We compared individual patient data and classifications obtained with six different IGF-I assay kits in a group of patients with various GH disorders.
In this cross-sectional study, we measured IGF-I with six immunoassays in 102 patients with active or treated acromegaly or GH deficiency. IGF-I normative data previously established for the same six assay kits were used to classify the patients (high, low, or normal IGF-I levels), using both raw data and standard deviation scores (SDSs). Pairwise concordance between assays was assessed with Bland-Altman plots and with the percentage of observed agreement and the weighted κ coefficient for categorized IGF-I SDS.
We observed marked variability both across each individual's IGF-I raw data and across IGF-I SDS values obtained with each of the six immunoassays. Pairwise concordance between assay values, as assessed with the weighted κ coefficient, ranged from 0.50 (moderate) to 0.81 (excellent).
Even when using normative data obtained in the same large population of healthy subjects and when using calculated IGF-I SDSs, agreement among IGF-I assay methods is only moderate to good. Differences in assay performance must be taken into account when evaluating and monitoring patients with GH disorders. This argues for the use of the same IGF-I assay for a given patient throughout follow-up.
胰岛素样生长因子 I（IGF-I）的测量对于生长激素（GH）紊乱的诊断和治疗至关重要。然而，根据检测技术的不同，患者的分类可能会有很大的差异。
我们比较了一组不同 GH 紊乱患者使用六种不同 IGF-I 检测试剂盒获得的个体患者数据和分类。
在这项横断面研究中，我们使用六种免疫测定法测量了 102 例活动性或治疗性肢端肥大症或 GH 缺乏症患者的 IGF-I。使用相同的六种检测试剂盒先前建立的 IGF-I 正常参考数据来对患者进行分类（高、低或正常 IGF-I 水平），同时使用原始数据和标准差评分（SDS）。使用 Bland-Altman 图评估了各检测试剂盒之间的一致性，并使用分类 IGF-I SDS 的观察一致性百分比和加权 κ 系数来评估。
我们观察到个体的 IGF-I 原始数据和使用六种免疫测定法获得的 IGF-I SDS 值都存在明显的变异性。使用加权 κ 系数评估的各检测试剂盒之间的一致性，范围从 0.50（中等）到 0.81（极好）。
即使使用相同大健康人群中获得的正常参考数据并使用计算出的 IGF-I SDS，IGF-I 检测方法之间的一致性也只是中等至良好。在评估和监测 GH 紊乱患者时，必须考虑检测方法的性能差异。这表明在整个随访过程中，应使用相同的 IGF-I 检测方法对特定患者进行评估。
