Department of Pathology, University of Chicago, Chicago, IL, US.
Clinical Laboratories, University of Chicago Medicine, Chicago, IL, US.
Am J Clin Pathol. 2023 Nov 2;160(5):455-465. doi: 10.1093/ajcp/aqad068.
The sensitivity and specificity of clot lysis at 30 minutes after maximum clot strength (LY30), as measured by thromboelastography (TEG), for clinically significant hyperfibrinolysis have not been compared across the 2 US Food and Drug Administration-approved instruments (the TEG 5000 and TEG 6s [Haemonetics]).
We performed a retrospective, single-center analysis of these 2 instruments using the kaolin (CK) reagent.
Local verification studies showed that the TEG 5000 and TEG 6s CK LY30 upper limits of normal (ULNs) were distinct (5.0% and 3.2%, respectively). Retrospective analysis of patient data showed that abnormal LY30 was 6 times more prevalent with the TEG 6s than with the TEG 5000 instrument. LY30 was a significant predictor of mortality with both instruments (TEG 6s: receiver operating characteristic [ROC] area under the curve [AUC] = 0.836, P ≤ .0001; TEG 5000: ROC AUC = 0.779, P = .028). The optimal LY30 cut point was determined based on these mortality data for each instrument. The TEG 6s showed superior mortality prediction than the TEG 5000 at lower LY30 levels (≥10%), with likelihood ratios of 8.22 and 2.62 for the TEG 6s and TEG 5000, respectively. Patients with a TEG 6s CK LY30 of 10% or higher were significantly more likely to die, receive cryoprecipitate, receive transfusions, or receive massive transfusion than patients with a TEG 6s LY30 of 3.3% to 9.9% (all P < .01). Patients with a TEG 5000 LY30 of 17.1% or higher were significantly more likely to die or use cryoprecipitate (P < .05); transfusion and massive transfusion protocol were not significantly different. Whole blood spiking studies showed that 70 ng/mL tissue plasminogen activator (tPA) achieved an average LY30 of approximately 10% for both instruments.
CK LY30 above the ULN is a sensitive but not specific cutoff for hyperfibrinolysis. At least moderately elevated CK LY30 carries more clinical portent on the TEG 6s instrument than on the TEG 5000. These TEG instruments are not sensitive to low concentrations of tPA.
血栓弹力描记法（TEG）测量的最大凝块强度后 30 分钟时（LY30）的纤维蛋白溶解灵敏度和特异性，尚未在 2 种美国食品和药物管理局批准的仪器（TEG 5000 和 TEG 6s [Haemonetics]）之间进行比较。
我们使用高岭土（CK）试剂对这 2 种仪器进行了回顾性单中心分析。
局部验证研究表明，TEG 5000 和 TEG 6s CK LY30 正常值上限（ULN）明显不同（分别为 5.0%和 3.2%）。对患者数据的回顾性分析表明，与 TEG 5000 仪器相比，TEG 6s 中异常 LY30 的发生率高 6 倍。LY30 是这两种仪器预测死亡率的重要指标（TEG 6s：ROC 曲线下面积[AUROC]为 0.836，P≤0.0001；TEG 5000：AUROC=0.779，P=0.028）。根据这些死亡率数据，为每种仪器确定了最佳 LY30 截断值。与 TEG 5000 相比，在较低的 LY30 水平（≥10%）下，TEG 6s 显示出更高的死亡率预测能力，其比值比分别为 8.22 和 2.62。TEG 6s CK LY30 为 10%或更高的患者明显更有可能死亡、接受冷沉淀、输血或大量输血，而 TEG 6s LY30 为 3.3%至 9.9%的患者则无（均 P<0.01）。TEG 5000 LY30 为 17.1%或更高的患者明显更有可能死亡或使用冷沉淀（P<0.05）；输血和大量输血方案无显著差异。全血加标研究表明，对于这两种仪器，70ng/mL 组织型纤溶酶原激活剂（tPA）可使平均 LY30 达到约 10%。
高于 ULN 的 CK LY30 是纤溶亢进的敏感但非特异性截断值。至少中等升高的 CK LY30 在 TEG 6s 仪器上比在 TEG 5000 仪器上具有更重要的临床意义。这些 TEG 仪器对低浓度的 tPA 不敏感。
