Diagnostic Criteria for Essential Thrombocytopaenia (ET)

Polycythemia Vera Study Group (PVSG) Diagnostic Criteria for Essential Thrombocytopaenia (ET)

All of the following criteria must be fulfilled to make a diagnosis of ET

  1. Platelet count greater than 600 x 109/L

  2. Hematocrit less than 40 or normal red blood cell mass

  3. Stainable iron in the marrow or normal RBC mean corpuscular volume (If these measurements suggest iron deficiency, polycythemia vera cannot be excluded unless a trial of iron therapy fails to increase the red blood cell mass into the polycythemic range.)

  4. No Philadelphia chromosome or bcr/abl gene rearrangement

  5. Collagen fibrosis of the bone marrow absent or less than one third of the biopsy area without both marked splenomegaly and a leukoerythroblastic blood film

  6. No cytogenetic or morphologic evidence for a myelodysplastic syndrome

  7. No cause for a reactive thrombocytosis

    Continue reading

Diagnostic Criteria for Heparin-Induced Thrombocytopenia (HIT)

Diagnostic Criteria for Heparin-Induced Thrombocytopenia (HIT)

  • Heparin exposure >5 days
  • Relative thrombocytopenia: decrease in platelet count by 50% from baseline OR absolute thrombocytopenia: decrease in platelet count to less than 100 to 150 x 109/L
  • Absence of other causes of thrombocytopenia
  • Development of new thrombosis, or extension of pre-existing thrombosis, while receiving heparin therapy
  • Confirmation by laboratory testing
  • Return to normal platelet count when heparin is discontinued Continue reading