Hereditary pyropoikilocytosis blood smear with RBC fragments miscounted as platelets, causing artefactual thrombocytosis (pseudothrombocytosis)

Peripheral blood smear from an asymptomatic individual with microcytic anemia. Automated CBC analysis showed Hb 10.7 g/dL, MCV 70.1 fL, MCH 23 pg, and platelet count of 874,000/microL. The blood smear had marked anisopoikilocytosis with fragmented RBCs, elliptocytes, Howell-Jolly bodies, and normal platelet number. EMA binding fluorescence intensity ratio was 0.84, and NGS identified a pathogenic variant in the alpha spectrin gene, SPTA1 (c.83G>A; p.Arg28His), consistent with HPP.

These findings demonstrate the importance of blood smear review to exclude thrombocytosis and confirm a RBC disorder as the cause.