Ambrose T M, Parvin C A, Mendeloff E, Luchtman-Jones L
Department of Pathology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Clin Chem. 2001 May;47(5):858-66.
The new Low-Range Heparin Management Test (LHMT), a method for point-of-care testing (POCT) of heparinization, has been designed to function at the low to moderate heparin concentrations typically found in patients undergoing extracorporeal membrane oxygenation (ECMO). In this study, the new method is compared with two POCT methods and a laboratory-based anti-Xa assay.
We obtained 760 whole blood samples from 13 patients undergoing ECMO. All samples were tested immediately by the LHMT, the Activated Clotting Time (ACT) test, and its low-range counterpart (ACT-LR). Aliquots from the same blood draw were frozen for later anti-Xa analysis using the Diagnostica Stago method on the Roche Cobas Fara-II.
The precision was best for duplicate citrated LHMT samples (CV = 3.1%). LHMT clotting times (overall median, 162 s) were typically shorter than ACT or ACT-LR times (247 and 235 s, respectively). The relationship between the LHMT and the other POCT methods differed significantly from patient to patient (P <0.0001), and a meaningful single relationship between the methods could not be obtained. The overall correlation coefficient between clotting time values and actual heparin concentrations was < or = 0.48 for each of the instruments tested, although time plots of each analyzer's data suggested that they detected heparin dosage changes within single patients.
The performance of the LHMT on the TAS Analyzer is equivalent to that of currently commercially available POCT methods. The lack of agreement between absolute clotting time values and heparin concentrations suggests the need for reexamination of current ECMO patient management strategy.
新型低范围肝素管理检测法（LHMT）是一种用于肝素化即时检验（POCT）的方法，其设计目的是在体外膜肺氧合（ECMO）患者中常见的低至中等肝素浓度下发挥作用。在本研究中，将这种新方法与两种POCT方法以及一种基于实验室的抗Xa检测法进行了比较。
我们从13例接受ECMO的患者中获取了760份全血样本。所有样本均立即用LHMT、活化凝血时间（ACT）检测法及其低范围对应检测法（ACT-LR）进行检测。同一血样的等分样本被冷冻，以便日后使用罗氏Cobas Fara-II上的Diagnostica Stago方法进行抗Xa分析。
枸橼酸盐抗凝的LHMT重复样本的精密度最佳（CV = 3.1%）。LHMT凝血时间（总体中位数为162秒）通常短于ACT或ACT-LR时间（分别为247秒和235秒）。LHMT与其他POCT方法之间的关系在患者之间差异显著（P <0.0001），无法获得这些方法之间有意义的单一关系。尽管各分析仪数据的时间图表明它们能检测出单例患者体内肝素剂量的变化，但对于每种检测仪器，凝血时间值与实际肝素浓度之间的总体相关系数均≤0.48。
LHMT在TAS分析仪上的性能与目前市售的POCT方法相当。绝对凝血时间值与肝素浓度之间缺乏一致性表明需要重新审视当前的ECMO患者管理策略。
