Barbieri U, Gandolfi C
Clin Chim Acta. 1977 Jun 15;77(3):257-67. doi: 10.1016/0009-8981(77)90228-5.
The preparation of 125I-labelled tracer for digoxin radioimmunoassay (125I monoiodinated 3-succinyl digoxigenin-1-tyrosine) is described, and its performance in radioimmunoassay of plasma samples is compared with that obtained with tritiated digoxin. The accuracy levels were assessed through the evaluation of different potential sources of systematic errors, such as interference from digoxin-related molecules and plasma proteins and methodological artefacts possibly associated with the immunocomplex instability, and through a series of checks including the recovery and parallelism tests and the correspondence of results obtained with the two tracers. The slope and the repeatability with time of the calibration curves and the spread of replicate estimates were taken into consideration to assess the assay precision. An essential equivalence in terms of reliability of measurement was proved for the two methodological variants, so that practical aspects and economic factors remain the main criteria to evaluate the relative merits: from this point of view, the advantages of using 125I-labelled tracer, as an alternative to tritiated digoxin, are discussed.
描述了用于地高辛放射免疫分析的125I标记示踪剂（125I单碘化3-琥珀酰洋地黄毒苷-1-酪氨酸）的制备，并将其在血浆样本放射免疫分析中的性能与用氚标记地高辛获得的性能进行了比较。通过评估不同潜在系统误差来源（如地高辛相关分子和血浆蛋白的干扰以及可能与免疫复合物不稳定性相关的方法学假象），并通过一系列检查（包括回收率和平行性测试以及两种示踪剂获得的结果的一致性）来评估准确度水平。考虑校准曲线的斜率和随时间的重复性以及重复估计值的离散度来评估分析精密度。证明了两种方法变体在测量可靠性方面基本等效，因此实际方面和经济因素仍然是评估相对优点的主要标准：从这个角度讨论了使用125I标记示踪剂替代氚标记地高辛的优点。
