To investigate the causes of ethylenediaminetetraacetic acid-dependent pseudothrombocytopenia (EDTA-PTPC), and to enhance the clinical understanding and attention to the occurrence of EDTA-PTPC in children.

The clinical data of a 4-year-old child in the First Hospital of Liangshan were retrospectively analyzed. The blood samples were treated with EDTA (37 ℃), sodium citrate and heparin anticoagulant. The platelet count changes were measured at 0, 15, 30, 45, 60, 90, 120, 150, and 180 minutes. Simultaneously, manual microscopy was performed to observe the agglutination of platelets.

The number of platelets in this child decreased when EDTA anticoagulant was used to treat blood samples. EDTA also showed a decrease in platelet count after a 37 ℃ water bath, while no such phenomenon was observed in the sodium citrate and heparin anticoagulant tubes. Manual smear microscopy showed that there was large clumping of PLT in the peripheral blood after EDTA anticoagulation, while no clumping was observed with other anticoagulants, confirming the diagnosis of EDTA-PTCP.

For children who experience thrombocytopenia without corresponding skin, mucosal, and visceral bleeding after anticoagulation with EDTA, EDTA-PTCP should be considered. To clarify the cause, further blood smear examination, manual platelet count, or use of sodium citrate and heparin for blood plate examination should be performed to avoid delaying diagnosis and treatment.