A 73 year old female is being evaluated for an elective left hip ORIF. Her platelets are found to be 55 x 109/L but “platelet clumping” is commented on her peripheral blood film. What is the cause of platelet clumping? Is this patient a surgical candidate?
Platelet clumping is caused by EDTA (Ethylenediaminetetraacetic acid), the anti-coagulant used in the collection tubes for a CBC.
Such results can be avoided by repeating the platelet count using a citrate tube, as citrate is an anticoagulant and should not interfere with platelet artifact.
So long as the repeat platelet count is acceptable, she should be stable for surgery.
Bain B. Diagnosis from the blood smear. N Engl J Med 2005;353:498-507.
