Department of Laboratory Medicine, University of Washington, Seattle, Washington 98195, USA.
Transfusion. 2010 Dec;50(12):2547-52. doi: 10.1111/j.1537-2995.2010.02753.x.
Evaluation of hemostasis in bleeding patients requires both accuracy and speed.
As an alternative to point-of-care testing, we developed an emergency hemorrhage panel (EHP: prothrombin time [PT], fibrinogen, platelet count, hematocrit) for use in making transfusion decisions on bleeding patients with a goal of less than 20-minute turnaround time (TAT) when performed in the clinical laboratory on automated instruments. Because point-of-care samples are not checked for clotting or hemolysis, we evaluated their effect on automated testing.
TAT was reduced by moving the sample immediately to testing and shortening centrifugation times. Clotting in samples was rare (1.1%) and shortened the PT by only 0.7 seconds. It lowered fibrinogen on average 18%, but resulted in only one of 2300 samples changing from normal to low fibrinogen. Hemolysis had no clinically significant effect on the PT or fibrinogen. Therefore, hemolysis checks were eliminated and clot checks minimized. Initially TAT averaged 15±4 minutes (range, 8-30min), but 9% of samples exceeded the 20-minute goal due to low fibrinogens that slowed testing. A revised fibrinogen assay with expanded calibration range resulted in a TAT of 14±3 minutes (range, 6-28min) with only 2% of samples exceeding the 20-minute goal. By limiting EHPs to patients that were actively bleeding, EHPs accounted for only 8 of 243 coagulation samples per day.
Limiting EHPs to bleeding patients and modifications to the process and assays used for hemostasis testing lead to TATs of less than 20 minutes for critical testing in the clinical laboratory.
评估出血患者的止血功能需要既准确又快速。
作为即时检测的替代方法,我们开发了一种紧急出血检测面板(EHP:凝血酶原时间[PT]、纤维蛋白原、血小板计数、血细胞比容),用于对有出血症状的患者进行输血决策,目标是在临床实验室使用自动化仪器进行检测时将周转时间(TAT)缩短至 20 分钟以内。由于即时检测的样本不检查凝血或溶血,因此我们评估了其对自动化检测的影响。
通过立即将样本转移到检测中并缩短离心时间,TAT 得以缩短。样本中的凝血很少见(1.1%),仅将 PT 缩短了 0.7 秒。它平均降低了 18%的纤维蛋白原,但仅导致 2300 个样本中的 1 个从正常纤维蛋白原变为低纤维蛋白原。溶血对 PT 或纤维蛋白原没有临床显著影响。因此,消除了溶血检查,并将凝块检查最小化。最初,TAT 平均为 15±4 分钟(范围 8-30 分钟),但由于纤维蛋白原较低而导致 9%的样本超过 20 分钟的目标,这会减缓检测速度。经过扩展校准范围的修订纤维蛋白原检测方法,TAT 缩短至 14±3 分钟(范围 6-28 分钟),仅有 2%的样本超过 20 分钟的目标。通过将 EHP 限制在有活动性出血的患者中,EHP 仅占每天 243 个凝血样本的 8 个。
将 EHP 限制在出血患者中,并对用于止血检测的流程和检测方法进行修改,可使临床实验室的关键检测的 TAT 缩短至 20 分钟以内。