What is spurious thrombocytopenia or pseudothrombocytopenia?

By William Aird

  • Thrombocytopenia that results from platelet clumping in vitro.
  • An in vitro artifact with no clinical consequence.
  • Usually caused by EDTA-dependent antibodies, but may also occur with poor specimen collection and/or handling.
This patient was a 67-year-old man with chronic kidney disease. Note the significant platelet clumping (arrows) on a blood smear from a sample obtained in EDTA-containing tube. Blood obtained this way yielded a falsely low platelet count ( pseudothrombocytopenia) which was corrected when blood was taken in a heparin-containing tube  (50x).