Leukoagglutination reported as platelet clumps.

Blood cell count was performed on an automated analyzer using an ethylenediaminetetraacetic acid (EDTA) blood specimen and showed normal hemoglobin and leukocytes (7.2 109/L), but a mild thrombocytosis (467 109/L). Platelet clumps were flagged by the cell counter. However, when the peripheral smear was reviewed, there was leukocyte agglutination (shown, left) rather than clumps of platelets. The cold agglutinin test was positive with relative anti-I specificity. Serology for Mycoplasma pneumoniae was positive (complement fixation test 1:32, reference value 1:16; microparticles agglutination 1:1280, reference value 1:40). When the blood was warmed at 37°C, the smear no longer showed leukoagglutination (shown, right).