The use of the dried blood spot (DBS) sampling technique has extended the scope of clinical research, particularly in children. The effects of different hematocrit levels (25–55%) and different blood volumes (7.5–30 μL) on the surface area of the blood spots were investigated using ImageJ® software. Variation in hematocrit levels between patients and inaccuracies in blood volumes applied to Guthrie cards can have a marked effect on analyte concentrations measured in DBS samples. The current study presents a validated model that links blood volume and hematocrit to the surface area of the blood spot. The final model showed that both factors affect the blood spot surface area, however, the positive effect of blood volume is higher than the negative effect of hematocrit. The measurement of surface area could be added as an additional quality control step in clinical studies that have adopted fixed volume DBS sampling for the quantification of the analytes. This approach can be used in estimating the hematocrit if this is not known for a patient or estimating the volume in spots that are visually different in size from the norm, i.e. technical error.

中文翻译：

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血细胞比容，血容量和干血斑的表面积-一种定量模型。

干血斑（DBS）采样技术的使用扩展了临床研究的范围，特别是在儿童中。使用ImageJ®软件研究了不同的血细胞比容水平（25–55％）和不同的血容量（7.5–30μL）对血斑表面积的影响。患者之间的血细胞比容水平的变化以及应用于Guthrie卡的血量不准确可能会对DBS样品中测得的分析物浓度产生显着影响。当前的研究提出了一个经过验证的模型，该模型将血容量和血细胞比容与血斑表面积联系在一起。最终模型表明，这两个因素都会影响血斑表面积，但是血容量的正效应高于血细胞比容的负效应。在采用固定体积DBS采样进行分析物定量的临床研究中，可以增加表面积的测量作为附加的质量控制步骤。如果患者不知道该方法，则可以使用该方法估算血细胞比容，也可以估算在视觉上与标准尺寸（即技术错误）不同的斑点的体积。