Jan T, Shaw M A, Baumann G
Department of Medicine, Northwestern University Medical School, Chicago, Illinois 60611.
J Clin Endocrinol Metab. 1991 Feb;72(2):387-91. doi: 10.1210/jcem-72-2-387.
GH-binding proteins (GH-BPs) in human blood theoretically may interfere with measurements of immunoreactive GH by forming complexes with GH and competing with antibody reagents for ligand. Indeed, results of serum GH obtained by immunoassays are known to differ markedly depending on the assay employed. To assess the potential role of circulating GH-BPs in this phenomenon, we systematically examined their effect on GH measurement in four RIAs and two immunoradiometric assays. In all except one RIA, the effect of the BPs on tracer binding to antibody was mildly inhibitory. In both immunoradiometric assays, BPs increased the nonspecific association of the tracer with the solid phase reagent. However, these effects were minor at the BP concentrations realistically encountered in practice. Furthermore, the impact of BPs on GH standard curves and final results was negligible because BP effects fall into the category of nonspecific or zero dose counts, which are subtracted during data reduction. We conclude that GH-BPs are only a minor disturbance in GH immunoassays, which is completely compensated for by conventional assay design. Disparities among results yielded by different assays are probably not due to BP interference.
人血液中的生长激素结合蛋白（GH-BP）理论上可能会通过与生长激素形成复合物并与抗体试剂竞争配体来干扰免疫反应性生长激素的测量。实际上，已知通过免疫测定获得的血清生长激素结果会因所采用的测定方法而有显著差异。为了评估循环GH-BP在这一现象中的潜在作用，我们系统地研究了它们在四种放射免疫分析（RIA）和两种免疫放射分析中的对生长激素测量的影响。除一种RIA外，在所有其他方法中，结合蛋白对示踪剂与抗体结合的影响均具有轻微抑制作用。在两种免疫放射分析中，结合蛋白均增加了示踪剂与固相试剂的非特异性结合。然而，在实际中遇到的结合蛋白浓度下，这些影响较小。此外，结合蛋白对生长激素标准曲线和最终结果的影响可以忽略不计，因为结合蛋白的影响属于非特异性或零剂量计数范畴，在数据处理过程中会被减去。我们得出结论，生长激素结合蛋白在生长激素免疫测定中只是一个小干扰因素，传统的测定设计可完全补偿这一干扰。不同测定方法所得结果之间的差异可能并非由于结合蛋白的干扰。
