a Laboratory of Pharmaceutical Analysis, Department of Pharmacy, National and Kapodistrian University of Athens , Athens , Greece.
b Laboratory of Biopharmaceutics-Pharmacokinetics, Department of Pharmacy, National and Kapodistrian University of Athens , Athens , Greece.
Scand J Clin Lab Invest. 2019 Sep;79(5):325-333. doi: 10.1080/00365513.2019.1622033. Epub 2019 Jun 1.
Dried blood spots (DBS) are formed by deposition of a small amount of blood on specific adsorbent paper and its physical drying. DBS are employed as a sampling method in several fields of life sciences and drug research. A concern about DBS is the so-called 'Hematocrit (Ht) effect', as a different Ht leads, due to different viscosity, to different spot size, affecting assay bias. Solutions have been proposed, including the correction of quantified concentrations with a suitable correction factor. In order to quantitatively assess Ht impact on the DBS measurements, a computational approach was developed and implemented in R language. First, the % relative error was modeled with respect to Ht. Then, Monte Carlo simulations were performed in virtual men/women populations with different Ht levels and the % relative error in relation to the Ht used for calibrators was quantified. An upper level for % relative error being a 'tolerable contribution' of Ht effect to % total analytical error was finally suggested, defining, for the first time, a potential Ht range for analysis of adults' samples, where correction of concentrations of unknown samples may be omitted. Such tolerable level for % relative error may be defined in each laboratory, also based on experimental parameters (type of paper and blood volume). Using a Ht calibration value representing the study population is fully rationalized, leading to reduced probability for concentration corrections. Regulatory criteria for bioanalysis can thus be targeted, moving towards wider utilization of DBS in human pharmacokinetic and clinical trials.
干血斑 (DBS) 通过将少量血液沉积在特定的吸附纸上并使其干燥而形成。DBS 被用作生命科学和药物研究的几个领域中的采样方法。人们对 DBS 的一个关注是所谓的“红细胞压积（Ht）效应”，因为不同的 Ht 会因不同的粘度而导致不同的斑点大小，从而影响分析偏差。已经提出了一些解决方案，包括用适当的校正因子校正定量浓度。为了定量评估 Ht 对 DBS 测量的影响，开发了一种计算方法，并在 R 语言中实现。首先，相对于 Ht 对 %相对误差进行建模。然后，在具有不同 Ht 水平的虚拟男性/女性人群中进行蒙特卡罗模拟，并量化相对于用于校准品的 Ht 的 %相对误差。最后建议将 %相对误差的上限定义为 Ht 效应对总分析误差的“可容忍贡献”，从而首次定义了分析成人样本的潜在 Ht 范围，在这种范围内，可能可以省略对未知样本浓度的校正。每个实验室都可以根据实验参数（纸张类型和血量）来定义可接受的 %相对误差水平。使用代表研究人群的 Ht 校准值是完全合理的，这降低了浓度校正的可能性。因此，可以针对生物分析的监管标准进行调整，从而更广泛地将 DBS 应用于人体药代动力学和临床试验中。
