Kline Jeffrey A, Williams Ginger W, Hernandez-Nino Jackeline
Emergency Medicine Research, Department of Emergency Medicine, Carolinas Medical Center, Charlotte, NC 28323-2861, USA.
Clin Chem. 2005 May;51(5):825-9. doi: 10.1373/clinchem.2004.044883. Epub 2005 Mar 11.
Pregnancy is known to increase the D-dimer concentration above the conventional normal threshold of 0.50 mg/L, leading to an increased false-positive D-dimer test when venous thromboembolism (VTE) is clinically suspected in a pregnant patient. Our aim was to determine the effect of normal pregnancy on the D-dimer concentration.
Healthy women who were seeking to become pregnant and had no preexisting condition known to increase the D-dimer concentration were identified. Quantitative D-dimer measurements (MDA turbidimetric assay) and fibrinogen assays were performed before conception, at each trimester, and at 4 weeks postpartum. Patients were excluded for fetal loss or preeclampsia.
A total of 50 women were enrolled in the study, and blood samples were obtained at preconception and all trimesters from 23 women. The mean (SD) preconception D-dimer concentration was 0.43 (0.49) mg/L, and 79% of women had a D-dimer concentration <0.50 mg/L. D-Dimer increased with each trimester such that only 22% of women in the second trimester and none (of 23) in the third trimester (95% confidence interval, 0-14%) had a D-dimer concentration <0.50 mg/L. We found no correlation between either the D-dimer and fibrinogen concentrations or between the increases in D-dimer and fibrinogen with pregnancy.
Normal pregnancy causes a progressive increase in circulating D-dimer. The D-dimer test has no use in ruling out VTE in the third trimester if a cutoff of 0.50 mg/L is used. A large management study is needed to establish new thresholds for the D-dimer to rule out VTE in each trimester.
众所周知，妊娠会使D - 二聚体浓度升高至超过传统正常阈值0.50mg/L，这导致在临床怀疑妊娠患者发生静脉血栓栓塞（VTE）时，D - 二聚体检测出现更多假阳性结果。我们的目的是确定正常妊娠对D - 二聚体浓度的影响。
确定了那些想要怀孕且无已知会增加D - 二聚体浓度的既往疾病的健康女性。在受孕前、妊娠各期及产后4周进行定量D - 二聚体测量（MDA比浊法）和纤维蛋白原检测。排除发生胎儿丢失或子痫前期的患者。
共有50名女性参与本研究，其中23名女性在受孕前及妊娠各期均采集了血样。受孕前D - 二聚体浓度的均值（标准差）为0.43（0.49）mg/L，79%的女性D - 二聚体浓度<0.50mg/L。D - 二聚体浓度随妊娠进展而升高，以至于妊娠中期只有22%的女性以及妊娠晚期（23名女性中）无一人（95%置信区间，0 - 14%）的D - 二聚体浓度<0.50mg/L。我们发现D - 二聚体浓度与纤维蛋白原浓度之间以及D - 二聚体和纤维蛋白原随妊娠的升高幅度之间均无相关性。
正常妊娠会导致循环D - 二聚体逐渐升高。如果采用0.50mg/L的临界值，D - 二聚体检测在妊娠晚期无法用于排除VTE。需要开展一项大型管理研究来确定各妊娠阶段排除VTE的D - 二聚体新临界值。
