Key Takeaways

✅ Abnormalities in thyroid function have been associated with several hematological abnormalities including anemia, changes in the mean corpuscular volume, other cytopenias and changes in primary and secondary hemostasis.

✅ Hypothyroidism associated with:

• Macrocytosis in up to 35% of patients.
• Anemia in 5-25% of patients, usually normocytic.
• A shift of the hemostatic balance towards a hypocoagulable and hyperfibrinolytic (bleeding) state, including acquired von Willebrand disease (VWD).

✅ Hyperthyroidism associated with:

• Anemia in 5-20% of patients, usually normocytic but occasionally microcytic.
• Thrombocytopenia, leukopenia, or pancytopenia in a minority of cases.
• A shift of the hemostatic balance towards a hypercoagulable and hypofibrinolytic (clotting) state.