Evolution of blood smear findings in thrombotic thrombocytopenic purpura (TTP)

A patient presented with anemia (hemoglobin 9.1 g/dL) and thrombocytopenia (platelet count 83,000/microL).

(A) Initial blood smear showing only rare schistocytes (arrow).

(B) Repeat blood smear 24 hours later showing a marked increase in schistocytes (arrows), confirming microangiopathic hemolytic anemia.

The patient was diagnosed with TTP and had ADAMTS13 activity <5%.