Laboratory Markers in the Diagnosis of Venous Thromboembolism

Abstract

Abstract-Selected blood tests may be useful in the diagnosis of venous thromboembolism (VTE), or in the identification of a congenital or acquired defect associated with the development of VTE. Several studies have shown the D-dimer assay to have a high negative predictive value but poor specificity when used in the detection of VTE. Yet in the emergency room setting, the D-dimer test may be useful if a detailed risk factor analysis for each patient is included in the diagnosis. The presence of such genetic thrombophilia markers as factor V Leiden, prothrombin 20210A mutation, and antiphospholipid antibodies significantly increases a patient's risk of a thrombotic event. The relative risk of thrombosis in factor V heterozygotes is at least 3 times higher than in the general population, whereas the increased risk of thrombosis in homozygotes is estimated to be 50-to 80-fold greater than those without the defect. Thromboembolic events are reported in approximately one third of antiphospholipid-positive patients. Other markers such as hyperhomocysteinemia and deficiencies of antithrombin, protein C, or protein S, when combined with the previous mutations, significantly increase a patient's risk of a thrombotic event. We feel that it is important to identify these ultra-high-risk patients to provide adequate counseling about the risk of thrombosis before elective surgical procedures. Often, lifelong anticoagulation may be needed as these patients and family members may need testing before taking birth control pills or hormonal replacement.

How I treat venous thrombosis in children

“…25 In addition, combined genetic prothrombotic risk factors have been shown to increase the risk for thrombus recurrence in children as well as adults. 35,36 We classify children with the above clinical characteristics as high risk and give careful consideration to initial therapy with TPA thrombolysis. Based on our published experience, we usually begin systemic TPA for thrombi with symptomatic onset less than 14 days before initiation of treatment, and local thrombolysis with thrombectomy via interventional radiology for longer-seated thrombi or severe clinical presentations.…”

Hereditary Deficiency of Protein C or Protein S Confers Increased Risk of Arterial Thromboembolic Events at a Young Age

“…These thrombophilic conditions include hereditary deficiencies of protein S, protein C, and antithrombin; factor V Leiden; the prothrombin G20210A mutation; high levels of clotting factors VIII, IX, and XI; and antiphospholipid antibodies. 1 Hereditary deficiencies of protein S, protein C, and antithrombin have been recognized as the most potent thrombophilic conditions for VTE. [2][3][4][5][6] Recently, we demonstrated that the concomitance of other thrombophilic defects further enhances the risk of VTE associated with these deficiencies.…”

Ππ SCATTERING

“…Brief accounts of this work were given elsewhere. [42] Figure 3 shows the preliminary results obtained for the total cross sections with t-channel isospin 0 and 1: We include pre-asymptotic contributions and assume that the Regge parametrization yields a decent approximation above 1.7 GeV. At lower energies, the uncertainties in that representation become larger than those in the sum over the partial waves, which is also shown.…”