Zweig M H, Csako G, Benson C C, Weintraub B D, Kahn B B
Clin Chem. 1987 Jun;33(6):840-4.
"Sandwich"-type assays are subject to positive interference by the patient's "heterophile" antibodies. If present, these bind to the animal immunoglobulins in the assay reagents, forming artefactual sandwiches indistinguishable from those formed with the analyte itself. Immunoglobulins from non-immunized animals, added to the assay reagents, can diminish this effect by blocking the patient's antibodies. Elsewhere, we studied several patients with anti-mouse immunoglobulin activity, whose serum gave spuriously high results for thyrotropin (TSH) concentrations. Here we have studied this phenomenon by adding, to pooled zero-TSH serum, antibodies to mouse, goat, and horse immunoglobulins and then assaying TSH by several other sandwich-type assays involving mouse monoclonal antibodies. Assays not supplemented with blocking immunoglobulins from mice or other animals were more susceptible to this effect. When large amounts of antibody were added, the antibody excess diminished the interference. However, the presence of blocking immunoglobulins could reverse such antibody excess, actually enhancing, instead of diminishing, the positive interference. Users should be aware that blocking immunoglobulins may diminish but not necessarily eliminate this problem with such assays.
“三明治”式检测易受患者“嗜异性”抗体的正向干扰。如果存在这些抗体，它们会与检测试剂中的动物免疫球蛋白结合，形成与由分析物自身形成的无法区分的人为“三明治”结构。向检测试剂中添加来自未免疫动物的免疫球蛋白，可以通过阻断患者抗体来减少这种影响。在其他地方，我们研究了几名具有抗小鼠免疫球蛋白活性的患者，他们的血清促甲状腺激素（TSH）浓度给出了假性高值结果。在此，我们通过向混合的零TSH血清中添加抗小鼠、山羊和马免疫球蛋白的抗体，然后用其他几种涉及小鼠单克隆抗体的“三明治”式检测方法检测TSH，来研究这一现象。未添加来自小鼠或其他动物的封闭免疫球蛋白的检测方法更容易受到这种影响。当添加大量抗体时，抗体过量会减少干扰。然而，封闭免疫球蛋白的存在可能会逆转这种抗体过量情况，实际上增强而非减少正向干扰。使用者应意识到，封闭免疫球蛋白可能会减少但不一定能消除此类检测方法中的这个问题。
