BACKGROUND In a whole blood coagulation test, the concentration of any in vitro diagnostic agent in plasma is dependent on the hematocrit level but its impact on the test result is unknown. OBJECTIVE The aim of this work was to clarify the effects of reagent concentration, particularly Ca2+, and to find a method for hematocrit estimation compatible with the coagulation test. METHODS Whole blood coagulation tests by dielectric blood coagulometry (DBCM) and rotational thromboelastometry were performed with various concentrations of Ca2+ or on samples with different hematocrit levels. DBCM data from a previous clinical study of patients who underwent total knee arthroplasty were re-analyzed. RESULTS Clear Ca2+ concentration and hematocrit level dependences of the characteristic times of blood coagulation were observed. Rouleau formation made hematocrit estimation difficult in DBCM, but use of permittivity at around 3 MHz made it possible. The re-analyzed clinical data showed a good correlation between permittivity at 3 MHz and hematocrit level (R2=0.83). CONCLUSIONS Changes in the hematocrit level may affect whole blood coagulation tests. DBCM has the potential to overcome this effect with some automated correction using results from simultaneous evaluations of the hematocrit level and blood coagulability.

中文翻译：

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同时评估介电血液凝固法中的血液凝固和血细胞比容水平。

背景技术在全血凝固测试中，血浆中任何体外诊断剂的浓度取决于血细胞比容水平，但是其对测试结果的影响尚不清楚。目的这项工作的目的是弄清试剂浓度，特别是Ca2 +的影响，并找到一种与凝血试验兼容的血细胞比容估算方法。方法采用介电血凝法（DBCM）和旋转血栓弹力法进行全血凝结试验，使用不同浓度的Ca2 +或不同血细胞比容水平的样品。重新分析先前进行过全膝关节置换术的患者的临床研究的DBCM数据。结果观察到明显的Ca2 +浓度和血细胞比容水平与凝血特征时间的相关性。Rouleau的形成使DBCM中的血细胞比容估计变得困难，但是在3 MHz附近使用介电常数使之成为可能。重新分析的临床数据显示3 MHz的介电常数与血细胞比容水平之间具有良好的相关性（R2 = 0.83）。结论血细胞比容水平的改变可能影响全血凝结试验。DBCM可以通过同时评估血细胞比容水平和血液凝固性的结果，通过一些自动校正来克服这种影响。