Clinical Chemistry Service, Department of Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, NY.
J Appl Lab Med. 2021 Nov 1;6(6):1476-1483. doi: 10.1093/jalm/jfab055.
The incorporation of monoclonal antibodies, such as daratumumab, into multiple myeloma treatment regimens has led to the issue of false-positive interference in both serum protein electrophoresis (SPEP) and immunofixation (IF). The Hydrashift assay removes daratumumab interference from IF, allowing for correct interpretation. Here, we retrospectively examined the use of the Hydrashift assay at a large cancer center and provide guidelines on its most appropriate use.
38 patients with distinct daratumumab peaks on their SPEP were selected and were used to quantify the daratumumab peak on SPEP using the Sebia Phoresis software. A retrospective review of all Hydrashift assays ordered at our institution from July 2018 to March 2020 was performed. Data collected included patient clone type, IF migration patterns, and Hydrashift result. Serial quantification of SPEP results was performed as the corresponding IF transitioned from a true positive to a false positive.
Daratumumab adds a maximum magnitude of 0.20 g/dL on SPEP. Serial SPEP quantification showed IF transitioned from true positive to false positive when M-spikes ranged from 0.09 g/dL to 0.11 g/dL. Over 20 months, our laboratory performed 280 Hydrashift assays on 96 patients, 43/96 of whom had comigrating daratumumab/IgG-K IF bands.
The Hydrashift assay is typically unnecessary in patients with large M-spikes, >0.25 g/dL, regardless of clone type. When patient history is available, we recommend the Hydrashift assay be used in patients with comigrating daratumumab/IgG-K bands with M-spikes of <0.25 g/dL.
单克隆抗体（如达雷妥尤单抗）的加入使多发性骨髓瘤的治疗方案发生了变化，导致血清蛋白电泳（SPEP）和免疫固定（IF）出现假阳性干扰。Hydrashift 检测可去除 IF 中的达雷妥尤单抗干扰，从而进行正确的解读。在此，我们回顾性地检查了在一个大型癌症中心使用 Hydrashift 检测的情况，并提供了其最恰当使用的指南。
选择 38 例 SPEP 上有明显达雷妥尤单抗峰的患者，并用 Sebia Phoresis 软件对 SPEP 上的达雷妥尤单抗峰进行定量。对我院 2018 年 7 月至 2020 年 3 月间所有的 Hydrashift 检测进行了回顾性分析。收集的数据包括患者的克隆类型、IF 迁移模式和 Hydrashift 结果。对 SPEP 结果进行了连续定量检测，因为 IF 从真阳性转变为假阳性。
达雷妥尤单抗在 SPEP 上的最大幅度为 0.20 g/dL。随着 M 峰范围从 0.09 g/dL 到 0.11 g/dL，SPEP 的连续定量显示 IF 从真阳性转变为假阳性。在 20 个月的时间里，我们的实验室对 96 名患者进行了 280 次 Hydrashift 检测，其中 43/96 名患者有达雷妥尤单抗/IgG-K 的 IF 带共迁移。
对于 M 峰较大的患者（>0.25 g/dL），无论克隆类型如何，Hydrashift 检测通常是不必要的。如果有患者病史，我们建议在 M 峰<0.25 g/dL 且有达雷妥尤单抗/IgG-K 带共迁移的患者中使用 Hydrashift 检测。
