Study of Ethylenediaminetetraacetic acid (EDTA) – Dependent Pseudothrombocytopenia – An Incidental but Important Finding

Objectives: To study EDTA–PTCP for its prevalence, association with different clinical states, medications and duration of anticoagulation of blood. Methods: In all cases 2 ml of blood sample is collected in K3-EDTA and CPT vials separately and subjected for different tests viz. Peripheral smear examination, manual platelet counts, comparison of platelet counts obtained by automated cell counter at 30 minutes of blood collection from both anticoagulants and with manual counts and analysis of data for any relationship with particular disease or drug intake. Results: Thus, prevalence of EDTA-PTCP was 0.07% of total haemograms and 4.9% of total thrombocytopenia. The mean manual platelet count in these cases was 222.63 x 109/L, whereas, in anticoagulated blood, the respective values in EDTA were 171.40 and 226.63 x 109 /L in CPT. Thus, platelet counts in EDTA anticoagulated blood are much lower than the actual counts by manual method or with CPT as anticoagulant. There was no specific association between EDTAPTCP and particular disease or medication. Conclusions: Recognization of EDTA-PTCP will prevent needless evaluations of thrombocytopenia and related therapeutic decisions, hence, importance of this study.

Pseudothrombocytopenia; Ethylenediaminetetraacetic acid; CPT (trisodium citrate, pyridoxal 5′-phosphate and Tris); Manual platelet count