Study On The Methods Of D-dimer Examination In Patients With Venous Thromboembolism

Objective: The plasma D-dimer is a soluble and ultimate degradation product that is released from crosslinked fibrin by plasmin. D-dimer is an importantmarker that reflect a hypercoagulable state, thrombosis, and fibrinolytic activity inthe body. In clinical practice, we often use Enzyme-linked immunosorbent assayand immunoturbidimetry to detect the level of plasma D-dimer. D-dimer’s epitope is present in the D domain of cross-linked fibrin degradation products. In this study, we use Western blot and immunoturbidimetry detect the expression ofplasma D-dimer.Methods: Selected50patients with diagnostic Venous thromboembolism fromthe First Affiliated Hospital of Dalian Medical University’s the department ofrespiratory from2009to2010as the VTE group;Selected50heathy patients withphysical examination from out-patients without medical history and family history ofthrombosis as the healthy control group.Selectedd50late pregnancy（>28weeks）as thepregnancy group.Selected50patients with diagnostic malignant tumor and withoutVenous thromboembolism in the department of medical oncology in the same period asmalignant tumor group. By using Western blot and immunoturbidimetry to detect theexpression of plasma D-dimer of the VTE group、the pregnancy group、the malignanttumor group,and compared with the healthy control group.Results:1. The detect results of Western blot: The expression of plasma D-dimer in theVTE group (1.2015±0.8829)is significantly higher than the healthy controlgroup(0.6479±0.3679),（Z=-2.686, P=0.007）, is significant difference. The pregnancygroup（0.9345±0.6148）is higher than the healthy control group,(t=-2.045, P=0.046), thedifference is statistically significance. The malignant tumor group（1.1812±1.034） is higher than the healthy control group,(Z=-2.058, P=0.040), the difference is statisticallysignificance. The VTE group compare with the pregnancy group and the malignanttumor group, the test statistic Z=-0.844, Z=-0.038, P=0.399, P=0.970,there is nosignficantly difference. By using Western blot to detect the plasma D-dimer of VTEpatients it’s sensitivity is52%,specificity is92%.The expression of high molecular weight cross-linked fibrin degradation products(FDP) in the VTE （4.2263±2.4011） is higher than the healthy control group（2.0345±0.7473）,(Z=-4.656, P=0.000), is significant difference. The pregnancygroup(3.0790±1.7069) is higher than the healthy control group,(Z=-2.044, P=0.041),the difference is statistically significance. The malignant tumor group(3.2498±2.1437)is higher than the healthy control group,（Z=-2.052, P=0.0400）, the difference isstatistically significance. The VTE group is higher than the pregnancy group and themalignant tumor, the test statistic Z=-1.965, Z=-1.998, P=0.049, P=0.046, thedifference is statistically significance. By using Western blot to detect the plasma FDPof VTE patients it’s sensitivity is58%,specificity is80%.The ratio of D-dimer and high molecular weight cross-linked fibrin degradationproducts in the VTE group（0.3318±0.1284） is higher than the healthy control group（0.2640±0.0882）,(Z=-1.980, P=0.048), the difference is statistically significance.The pregnancy group(0.3955±0.0.0715) is higher than the healthy control group,(Z=-4.038, P=0.000), the difference is statistically significance. The malignant tumorgroup（0.4048±0.0867）is higher than the healthy control group,(Z=-4.215, P=0.000),the difference is statistically significance. The pregnancy group and the malignant tumoris higher than the VTE group,the test statistic t=-2.343, t=-2.053, P=0.025, P=0.044,the difference is statistically significance. By using Western blot to detect the ratio ofD-dimer and high molecular weight cross-linked fibrin degradation products FDP ofVTE patients it’s sensitivity is50%,specificity is74%.2. The detect results of immunoturbidimetry:the concentration of D-dimer in the VTE group(468.04±374.17ng/ml) is higher than the healthy control group(137.18±183.41ng/ml),(Z=-4.708, P=0.000), is significant difference. The pregnancy group(257.21±201.95ng/ml) is higher than the healthy control group,(Z=-2.876, P=0.004), is significant difference. The malignant tumor group(299.42±432.50ng/ml) is higher than the healthy control group, the test statistic Z=-2.902, P=0.004, is significant difference. The VTE group is higher than the pregnancy group and the malignant tumor group, the test statistic Z=-2.351, Z=-2.508, P=0.019, P=0.012,,the difference is statistically significance.By using immunoturbidimetryto detect the plasma D-dimer of VTE patients,it’s sensitivity is60%,specificity is92%.Conclusions:1. Confirmed by Western blot, the immunoturbidimetry commonly used in clinicalto detect the expression of plasma D-dimer, its monoclonal antibody identify proteinsconclude high molecular weight cross-linked fibrin degradation products FDP withD-dimer epitope,which is predominate.2. The high molecular weight cross-linked fibrin degradation products FDP in theVTE patients is higher than the pregnancy group and the malignant tumor group. Theratio of D-dimer and high molecular weight cross-linked fibrin degradation productsFDP in the pregnancy group and the malignant tumor group is higher than the VTEgroup, May provide a sensitive and specific indicator for the identification of threegroups of patients.