Hematocrit (HCT) measurements of blood from patients, blood donors and athletes are routinely performed on a daily basis. These measurements are often performed in centralized hospital labs by whole blood analyzers, which leads to long time-to-result. On site measurements, based on centrifugation can be done, but these assays require manual handling, are slow and can just measure HCT in contrast to the central lab whole blood analyzers. In this work, we present a microfluidic based method to measure HCT in blood samples by acoustic separation of whole blood into discrete regions of plasma and red blood cells. Comparison of the areas of the red blood cell and plasma regions gives an accurate HCT value, with a linear correlation to the centrifugation-based reference method. A readout can be performed within 2 s of acoustic actuation providing a readout accuracy of approximately 3% points (pp) HCT. Additional accuracy can be achieved by extending the acoustic actuation to 20 s, yielding an error of less than 1 pp HCT. This acoustic tool is optimal for integration into a lab-on-a-chip device with in-line measurements of different clinical parameters.

中文翻译：

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声流体血细胞比容测定

每天对患者、献血者和运动员的血液进行血细胞比容 (HCT) 测量。这些测量通常由全血分析仪在集中的医院实验室中进行，这会导致出结果的时间很长。可以进行基于离心的现场测量，但这些检测需要手动处理，速度较慢，并且与中央实验室全血分析仪相比只能测量 HCT。在这项工作中，我们提出了一种基于微流体的方法，通过将全血声分离成血浆和红细胞的离散区域来测量血液样本中的 HCT。红细胞和血浆区域的面积比较给出了准确的 HCT 值，与基于离心的参考方法呈线性相关。可以在声学驱动的 2 秒内执行读数，提供大约 3% 点 (pp) HCT 的读数精度。通过将声学驱动延长到 20 秒，可以实现额外的精度，产生小于 1 pp HCT 的误差。这种声学工具最适合集成到具有不同临床参数在线测量功能的芯片实验室设备中。