Jennings Ian, Woods Timothy A L, Kitchen Dianne P, Kitchen Steve, Walker Isobel D
United Kingdom National External Quality Assassment Scheme for Blood Coagulation, Rutledge Mews, 3 Southbourne Road, Sheffield S10 2QN, UK.
Thromb Haemost. 2007 Nov;98(5):1127-35. doi: 10.1160/th07-05-0377.
Accurate and precise measurement of plasma D-dimer levels is important in the diagnosis and management of venous thromboembolism. Considerable variability in D-dimer results obtained using different methods has, however, been reported in multicentre studies. This study explored in two separate multicentre exercises the degree of precision amongst laboratory D-dimer measurements, and the degree by which inter-method agreement could be improved using a calibration curve model. The first exercise demonstrated generally good within-centre precision, with 82% of the centres reporting results for two identical but differently coded samples within 10% of each other. However, six centres reported results which would have excluded deep vein thrombosis (DVT) for one sample but failed to exclude DVT for the other, identical sample. In the second exercise, overall between-method precision of D-dimer results for two samples was shown to improve markedly when a calibration model was applied, using the consensus median values obtained by all participants for three "calibration plasmas" to recalculate D-dimer values. For centres reporting results in fibrinogen equivalent units (FEUs), between-centre coefficients of variation (CVs) fell from 25.9% to 11.6% and 22.4% to 7.7%, respectively, for the two samples. For centres reporting in ng/ml, CVs fell from 45.3-21.6% and 40.8-11.6%, respectively. In conclusion, improved harmonisation of D-dimer results by different methods may be achieved by a calibration model and common calibrant plasmas.
准确精确地测量血浆D-二聚体水平对于静脉血栓栓塞症的诊断和管理至关重要。然而，多中心研究报告称，使用不同方法获得的D-二聚体结果存在相当大的变异性。本研究在两项独立的多中心实验中探讨了实验室D-二聚体测量的精密度程度，以及使用校准曲线模型可在何种程度上提高方法间的一致性。第一项实验表明各中心内部的精密度总体良好，82%的中心报告的两个相同但编码不同的样本结果彼此相差在10%以内。然而，有六个中心报告的结果显示，其中一个样本的结果会排除深静脉血栓形成（DVT），而另一个相同样本的结果却未能排除DVT。在第二项实验中，当应用校准模型时，使用所有参与者针对三种“校准血浆”获得的共识中位数重新计算D-二聚体值，两个样本的D-二聚体结果的总体方法间精密度显著提高。对于报告结果以纤维蛋白原当量单位（FEU）表示的中心，两个样本的中心间变异系数（CV）分别从25.9%降至11.6%以及从22.4%降至7.7%。对于报告结果以ng/ml表示的中心，CV分别从45.3 - 21.6%以及40.8 - 11.6%下降。总之，通过校准模型和通用校准血浆可实现不同方法间D-二聚体结果更好的一致性。
