Background Platelet (PLF) clumping occurring in pseudothrombocytopenia (PTCP) can result in inaccurate PLT.Automated platelet clump count (APCC) is a quantitative parameter of platelet aggregation.In this study,we evaluated the clinical utility of APCC in the screening for platelet aggregation related ethylene diamine tetraacetic acid (EDTA)-dependent PTCP (EDTA-PTCP).Methods A total of 105 patients and 200 healthy individuals were enrolled in this study.Blood samples were collected with dipotassium EDTA and sodium citrate respectively.ADVIA 2120 hematology analyzer was used to perform complete blood count (CBC) and APCC.Blood smears of both EDTA- and citrate-anticoagulated samples were made for microscope observation and manual PLT counting.Results In 25 patients with EDTA-PTCP patients,for EDTA-2K anticoagulated-blood,PLT was (55±6)×109/L,significantly lower than citrate anticoagulated blood ((186±13)×109/L)).APCC was (905±694)×109/L,significantly higher than citrate anticoagulated blood (98±37)×109/L.In true thrombocytopenia and healthy control groups,APCC was (63±60)×109/L and (69±59)×109/L respectively and there was no significant difference between EDTA and citrate anticoagulants.Receiver operator characteristic (ROC) curve showed both sensitivity and specificity of APCC were 96％ when the cutoff value of APCC was set as 182×109/L.Other platelet parameters had poor performance.Conclusion The APCC has a good sensitivity and specificity in differentiating EDTA-PTCP from true thrombocytopenia compared with other platelet parameters.