What is the role of platelet function and coagulation testing in the workup of polycythemia vera (PV)?

Updated: Aug 20, 2019
  • Author: Srikanth Nagalla, MBBS, MS, FACP; Chief Editor: Koyamangalath Krishnan, MD, FRCP, FACP  more...
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Answer

Abnormal platelet function (as measured by platelet aggregation tests with epinephrine, adenosine diphosphate [ADP], or collagen) may be demonstrated, but bleeding time may be normal. Some patients' platelet-rich plasma spontaneously aggregates without the addition of any of the above substances. This indicates a propensity for thromboses.

Routine coagulation test results are normal, with a high turnover rate for fibrinogen. The prothrombin time (PT) and activated partial thromboplastin (aPTT) time may be artifactually prolonged, however, because the erythrocytosis results in the collection of a low amount of plasma in relation to the anticoagulant in the test tube. Thus, the volume of the ratio of anticoagulant to blood must be modified when drawing blood for coagulation tests in patients who are polycythemic.


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