Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
Department of Association for Quality Assessment in Therapeutic Drug Monitoring and Clinical Toxicology (KKGT), Quality Assessment in Medical Laboratories (SKML), Nijmegen, the Netherlands; and.
Ther Drug Monit. 2023 Feb 1;45(1):61-68. doi: 10.1097/FTD.0000000000001019. Epub 2022 Aug 13.
Therapeutic drug monitoring (TDM) of immunosuppressive drugs is important for the prevention of allograft rejection in transplant patients. Several hospitals offer a microsampling service that provides patients the opportunity to sample a drop of blood from a fingerprick at home that can then be sent to the laboratory by mail. The aim of this study was to pilot an external quality control program.
Fourteen laboratories from 7 countries participated (fully or partly) in 3 rounds of proficiency testing for the immunosuppressants tacrolimus, ciclosporin, everolimus, sirolimus, and mycophenolic acid. The microsampling devices included the following: Whatman 903 and DMPK-C, HemaXis, Mitra, and Capitainer-B. All assays were based on liquid chromatography with tandem mass spectrometry. In round 2, microsamples as well as liquid whole blood samples were sent, and 1 of these samples was a patient sample.
Imprecision CV% values for the tacrolimus microsamples reported by individual laboratories ranged from 13.2% to 18.2%, 11.7%-16.3%, and 12.2%-18.6% for rounds 1, 2, and 3, respectively. For liquid whole blood (round 2), the imprecision CV% values ranged from 3.9%-4.9%. For the other immunosuppressants, the results were similar. A great variety in analytical procedures was observed, especially the extraction method. For the patient sample, the microsample results led to different clinical decisions compared with that of the whole blood sample.
Immunosuppressant microsampling methods show great interlaboratory variation compared with whole blood methods. This variation can influence clinical decision-making. Thus, harmonization and standardization are needed. Proficiency testing should be performed regularly for laboratories that use immunosuppressant microsampling techniques in patient care.
治疗药物监测（TDM）对于预防移植患者的移植物排斥反应非常重要。一些医院提供微采样服务，使患者有机会在家从指尖采集一滴血样，然后通过邮件将其送到实验室。本研究的目的是试行一个外部质量控制计划。
来自 7 个国家的 14 个实验室参与了 3 轮针对免疫抑制剂他克莫司、环孢素、依维莫司、西罗莫司和霉酚酸的能力验证。微采样设备包括以下几种：Whatman 903 和 DMPK-C、HemaXis、Mitra 和 Capitainer-B。所有检测均基于液相色谱-串联质谱法。在第 2 轮中，除了发送全血样品外，还发送了微样本，其中一个样本是患者样本。
各个实验室报告的他克莫司微样本的精密度 CV%值在第 1、2 和 3 轮中分别为 13.2%-18.2%、11.7%-16.3%和 12.2%-18.6%。对于全血（第 2 轮），精密度 CV%值为 3.9%-4.9%。对于其他免疫抑制剂，结果相似。观察到分析程序的多样性很大，特别是萃取方法。对于患者样本，与全血样本相比，微样本的结果导致了不同的临床决策。
与全血方法相比，免疫抑制剂微采样方法显示出很大的实验室间差异。这种差异可能会影响临床决策。因此，需要进行协调和标准化。对于在患者护理中使用免疫抑制剂微采样技术的实验室，应定期进行能力验证。
