Laboratory tests for protein C deficiency

Authors

  • Bernard Khor,

    1. Department of Pathology, Massachusetts General Hospital, Boston, Massachussets
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  • Elizabeth M. Van Cott

    Corresponding author
    1. Department of Pathology, Massachusetts General Hospital, Boston, Massachussets
    • Coagulation Laboratory, Massachusetts General Hospital, Gray-Jackson 235, 55 Fruit Street, Boston 02114, MA
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  • Conflict of interest: Nothing to report

Abstract

Hereditary protein C deficiency is a hypercoagulable state associated with an increased risk for venous thrombosis. The recommended initial test for protein C is an activity (functional) assay, which may be clotting time based or chromogenic. The advantages and disadvantages of the various testing options are presented. The causes of acquired protein C deficiency are much more common than hereditary deficiency. Therefore, this article describes the appropriate steps to take when protein C activity is low, to confirm or exclude a hereditary deficiency. The causes of falsely normal results are also described, including lupus anticoagulants and direct thrombin inhibitors. Am. J. Hematol., 2010. © 2010 Wiley-Liss, Inc.

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