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Clinical Coagulation Division

The Clinical Coagulation Division is involved in clinical testing, research and teaching related to bleeding and thrombotic disorders.

Clinical Coagulation Faculty

Daniel E. Sabath, MD, PhD, Division Head, Director, Hematology Division, Coagulation, Red Cell Disorders, and Molecular Diagnosis

Diagnostic Testing

A comprehensive set of clinical tests are available for the diagnosis and monitoring of bleeding and thrombotic disorders.

Testing for hypercoagulable states:

  • Inherited coagulation disorders including Antithrombin deficiency, Protein C deficiency, Protein S deficiency and elevated Chromogenic VIII (with C‑reactive protein to exclude acute phase response). Tests may be ordered individually or as a panel with an interpretive report.
  • Lupus inhibitor testing (meeting current International Society of Hemostasis and Thrombosis standards) including the dilute Russell viper venom test, hexagonal phase phospholipid test, and testing for antibodies against cardiolipin and B2‑glycoprotein I (performed in UW Immunology laboratory). Tests may be ordered individually or as a panel with an interpretive report.
  • D‑dimer testing to assess the presence of acute thrombosis or resolution of thrombosis after therapy.
  • DNA testing for Factor V Leiden and Prothrombin mutations is offered by the UW Genetics laboratory.

Testing for bleeding disorders:

  • Assays for specific clotting factors (II, V, VII, VIII, IX, X, XI, XII).
  • Testing for specific coagulation factor inhibitors, including inhibitors of Factors VIII, IX, and V.
  • Von Willebrand Disease testing including Factor VIII activity, von Willebrand Factor antigen and activity assays, and von Willebrand Factor multimer analysis, including interpretive report.
  • Platelet function studies including the PFA‑100 assay with ADP/collagen and epinephrine/collagen and platelet aggregometry studies measuring aggregation with impedance and granule release (ATP/luciferin assay). Interpretive reports are issued for aggregometry studies.

Anticoagulant drug testing:

  • Anti‑Xa assays to monitor therapy with unfractionated heparin, low molecular weight heparins such as enoxaparin (Lovenox) or fondaparinux (Arixtra)
  • Direct thrombin inhibitor assay (to assess bivalrudin or argatroban effect)
  • Dabigatran (Pradaxa) – uses dilute thrombin time assay
  • Rivaroxaban (Xarelto) – uses anti‑Xa assay
  • Apixaban (Eliquis) – uses anti‑Xa assay
  • VerifyNow assay to assess resistance to therapy with clopidogrel (Plavix), prasugrel (Effient) or aspirin.

Testing for heparin‑induced thrombocytopenia:

  • Enzyme‑linked immunoassay for heparin‑PF4 IgG antibodies.
  • Reflexive serotonin release assay (sendout test) after positive heparin‑PF4 antibody test.


  • Measure the mechanical properties of a developing blood clot and the efficiency of blood coagulation in whole blood.

Group/panel testing:

  • ANTI‑PHOSPHOLIPIDS GROUP/CARDIOLIPINS - Includes Anti‑Beta‑2‑glycoprotein‑1, Anti‑cardiolipins, IgA, IgG, IgM
  • LUPUS ANTICOAGULANT – Includes Lupus Inhibitor, Antiphospholipid Group/Cardiolipins
  • VON WILLEBRAND DISEASE GROUP – Includes Von Willebrand Factor Antigen, Factor VIII Activity, Von Willebrand Factor Multimer and VWF Collagen Binding
    • Venous – Includes Activated Protein C Resistance, Antithrombin, Protein C Activity, Protein‑S Free Antigen, and Lupus Inhibitor
    • Comprehensive Venous – includes Venous Panel, chromogenic factor VIII, C‑reactive protein, and Prothrombin DNA screen.


Lab Medicine Coagulation welcomes collaboration with researchers. Testing available includes clinical testing as above, as well as non‑clinical research‑only testing (such as PIVKA II, Thrombin/Antithrombin, Prothrombin Fragment 1.2 , Human p‑Selectin). Please contact laboratory for more information.


The Clinical Coagulation Division participates in training programs for undergraduate medical laboratory science students, medical students, clinical pathology residents and hematopathology fellows. In addition, a Master of Science degree is offered in Laboratory Medicine with concentration in the Clinical Coagulation area. Please see Education section for more information.


  • University of Washington Clinical Coagulation Lab
  • 1959 NE Pacific Street
  • Room NW220
  • Seattle, WA 98195
  • Tel: (206) 598‑6242

  • Harborview Medical Center Clinical Coagulation Lab
  • 325 9th Ave
  • Room GWH 47
  • Seattle, WA 98195
  • Tel: (206) 744‑3128

Last updated: 9/28/2015