EDTA-dependent pseudothrombocytopenia in a child.

Area of Science:

• Hematology
• Clinical Pathology

Background:

• Ethylenediaminetetraacetic acid (EDTA)-dependent pseudothrombocytopenia (PTCP) is a common cause of spurious thrombocytopenia.
• PTCP is characterized by in vitro platelet clumping in EDTA-anticoagulated blood, leading to falsely low platelet counts.
• Platelet aggregation in PTCP is typically inhibited by alternative anticoagulants like heparin or sodium citrate.

Observation:

• This report details a rare case of a 10-year-old boy exhibiting both EDTA- and heparin-dependent PTCP.
• The patient presented with spuriously low platelet counts when blood was anticoagulated with EDTA and heparin.
• Platelet aggregation was notably absent in blood samples anticoagulated with sodium citrate, which yielded normal platelet counts.

Findings:

• EDTA and heparin, in addition to causing platelet clumping, can induce spuriously low platelet counts.
• Sodium citrate effectively prevented platelet aggregation and maintained accurate platelet counts in this patient.
• This case highlights a rare dual dependency of PTCP on both EDTA and heparin.

Implications:

• The findings suggest that heparin should be considered as a potential inducer of pseudothrombocytopenia, alongside EDTA.
• Accurate platelet counting in patients with suspected PTCP may require the use of sodium citrate as an anticoagulant.
• This case broadens the understanding of anticoagulant-induced platelet aggregation and its clinical diagnostic challenges.