Volumetric absorptive microsampling (VAMS) is an innovative alternative strategy to venipuncture for monitoring tacrolimus levels in transplant recipients. In this study, we aimed to validate a new high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for quantifying tacrolimus in blood collected by VAMS. Tacrolimus was extracted from dried blood tips in an original process involving sonication, protein precipitation and salting out. The assay was validated in accordance with EMA and IATDMCT guidelines. For clinical validation, the tacrolimus concentrations measured in liquid venous whole blood (with the reference method) were compared with those measured in capillary whole blood collected simultaneously with VAMS by a nurse. The assay was then used to monitor tacrolimus exposure in transplant recipients. The method was linear, sensitive and fast. Within-day and between-day precisions and overall bias were within ±15%. No significant hematocrit effect was observed. The matrix effect was negligible and recovery exceeded 80% for every concentration and hematocrit levels. Tacrolimus was stable in blood collected by VAMS for 1 week at room temperature, 48 h at 60 °C and 4 °C and 1 month at −80 °C. Clinical validation (n = 42 paired samples) demonstrated a strong correlation between the two methods (r = 0.97 Pearson correlation). Bland-Altman analysis revealed that more than 90% of the differences between VAMS and liquid blood paired concentrations were within the ±20% acceptable range. The method had a satisfactory analytical performance and fulfilled clinical requirements. This minimally invasive VAMS-based assay appears reliable for the determination of tacrolimus levels in blood from transplanted patients.

体积吸收微采样（VAMS）是一种创新的替代静脉穿刺策略，用于监测移植受者中他克莫司的水平。在这项研究中，我们旨在验证一种新的高效液相色谱-串联质谱（HPLC-MS / MS）方法，用于定量VAMS采集的血液中他克莫司。他克莫司是从干血尖中提取的，其原始过程涉及超声处理，蛋白质沉淀和盐析。根据EMA和IATDMCT指南对测定进行了验证。为了进行临床验证，将护士在液体静脉全血中（使用参考方法）测得的他克莫司浓度与在与VAMS同时采集的毛细管全血中测得的他克莫司浓度进行了比较。然后将该测定法用于监测移植接受者中他克莫司的暴露。该方法线性，灵敏且快速。日内和日间精度和整体偏差在±15％以内。没有观察到明显的血细胞比容效应。每种浓度和血细胞比容水平的基质效应都可以忽略不计，回收率超过80％。他克莫司在VAMS采集的血液中在室温下稳定1周，在60°C和4°C下48 h稳定，在-80°C下1个月稳定。临床验证（n  = 42个配对样本）证明了这两种方法之间的强相关性（r = 0.97皮尔逊相关性）。Bland-Altman分析显示，VAMS和液态血液配对浓度之间的差异超过90％在可接受的±20％范围内。该方法具有令人满意的分析性能并满足临床要求。这种基于VAMS的微创检测方法对于确定移植患者血液中他克莫司的含量似乎是可靠的。