Parunov L A, Surov S S, Liang Y, Lee T K, Ovanesov M V
Office of Tissues and Advanced Therapies, CBER, US Food and Drug Administration, Silver Spring, MD, USA.
Center for Theoretical Problems of Physicochemical Pharmacology, Moscow, Russia.
Haemophilia. 2017 May;23(3):466-475. doi: 10.1111/hae.13174. Epub 2017 Feb 15.
Thrombin generation test (TGT) is a global haemostasis assay with a potential to predict bleeding tendencies and treatment effects in patients with haemophilia. Despite 15 years of clinical research, the diagnostic value of TGT remains controversial, possibly due to suboptimal sensitivity to coagulation deficiencies, robustness and reproducibility.
The goal of this study was to explore the effect of calcium chloride (CaCl ) concentration on the TGT's response to intrinsic coagulation factors (F) VIII, IX and XIa.
Normal and factor-deficient plasmas supplemented with lacking coagulation factor and different CaCl levels were tested by calibrated thrombinography assay.
Thrombin peak height (TPH) was strongly CaCl dependent, increasing sharply from no TG at 5 mm to a peak at 13.8 mm of CaCl (95% confidence interval [CI]: 13.0, 14.5) in normal and normalized deficient plasmas and at 11.9 mm (CI: 9.7, 14.2) in deficient plasmas, and then decreasing slowly to a complete inhibition at 30-40 mm. In contrast, TG lag time, time to peak and endogenous thrombin potential were nearly insensitive to CaCl concentrations between 10 and 20 mm. The maximal difference between the TPH in deficient and supplemented plasmas was observed at 15.5 mm (CI: 12.8, 18.1).
Variations in CaCl concentration in the assay mixture and sodium citrate concentrations in patient plasma samples may affect TGT responses, sensitivity and result in increased inter- and intra-laboratory variance. Implementation of TGT by clinical and quality control laboratories may require optimization of CaCl concentration.
凝血酶生成试验（TGT）是一种全面的止血检测方法，有潜力预测血友病患者的出血倾向和治疗效果。尽管经过了15年的临床研究，但TGT的诊断价值仍存在争议，这可能是由于其对凝血缺陷的敏感性欠佳、稳健性和可重复性不足。
本研究的目的是探讨氯化钙（CaCl₂）浓度对TGT对内源性凝血因子VIII、IX和XIa反应的影响。
通过校准凝血酶图谱分析法对补充了缺乏的凝血因子和不同CaCl₂水平的正常血浆和因子缺乏血浆进行检测。
凝血酶峰值高度（TPH）强烈依赖于CaCl₂，在正常血浆和校正后的缺乏血浆中，从5 mmol/L时无凝血酶生成急剧增加到CaCl₂为13.8 mmol/L时达到峰值（95%置信区间[CI]：13.0，14.5），在缺乏血浆中为11.9 mmol/L（CI：9.7，14.2），然后在30 - 40 mmol/L时缓慢下降至完全抑制。相比之下，凝血酶生成滞后时间、达到峰值的时间和内源性凝血酶潜力在10至20 mmol/L的CaCl₂浓度范围内对其几乎不敏感。在15.5 mmol/L（CI：12.8，18.1）时观察到缺乏血浆和补充血浆中TPH的最大差异。
检测混合物中CaCl₂浓度和患者血浆样本中柠檬酸钠浓度的变化可能会影响TGT反应、敏感性，并导致实验室间和实验室内差异增加。临床和质量控制实验室实施TGT可能需要优化CaCl₂浓度。
