This article is only available in the PDF format. Download the PDF to view the article, as well as its associated figures and tables.
To the Editor.—
In their recent article (227:628, 1974), Kjeldsberg and Hershgold pointed out several conditions that may result in artifactual thrombocytopenia when platelet counts are made by automated methods.We recently saw a patient with still another type of pseudothrombocytopenia. She is 83 years old and was referred from another hospital because of rectal bleeding and "thrombocytopenia," with a platelet level of "10,000"/cu mm. There were no petechiae or ecchymoses, and the bleeding was localized to an anal fissure. The automated platelet count was 60,000/cu mm. However, the peripheral smear showed large masses of platelets that were clumped (Figure), and platelet clumping in an edetic acid-treated specimen made counting by phase microscopy unreliable. Platelet clumping also occurred in oxalated, citrated, and heparinized blood and was present to a slightly less degree in nonanticoagulated capillary blood obtained by fingerstick.The patient's serum did not contain platelet antibodies by the51
Cimo PL. Pseudothrombocytopenia. JAMA. 1974;229(7):766-767. doi:10.1001/jama.1974.03230450016011