title: EDTA-dependent pseudothrombocytopaenia: a 12-month epidemiological study.
abstract: The phenomenon of in vitro platelet clumping and consequent pseudothrombocytopaenia in the presence of EDTA has been studied in 33,623 subjects referring to a general hospital in a 1-year period. The observed frequency was 0.13%. EDTA-dependent pseudothrombocytopaenia (PTP) was suspected when a routine blood counting by the Coulter S-Plus IV/D showed a peculiar leucocyte histogram and pseudoleucocytosis. Confirmation was obtained by the manual count and by the finding of platelet aggregates in a stained blood smear. EDTA-dependent PTP was diagnosed when the platelet number and the morphological examination of blood anticoagulated with sodium citrate from the same patient were normal. EDTA-dependent PTP was found in 23 subjects aged from 19 to 79 years (0.068% of the study population): 17 were patients suffering from miscellaneous diseases, while six were apparently healthy. As a rule, platelet clumping was evident within 60 minutes from blood collection, but a longer latency (2-3 h) was observed in a few cases. EDTA-dependent PTP is a rare, but misleading phenomenon, the recognition of which is important in order to avoid expensive and potentially harmful procedures.
authors.affiliation: Department of Medicine, Istituto Scientifico S. Raffaele, Milano, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Vicari
authors.forename: G
authors.initials: G
authors.lastname: Banfi
authors.forename: P A
authors.initials: PA
authors.lastname: Bonini
mesh_terms: D000328:Adult; D000368:Aged; D003951:Diagnostic Errors; D004492:Edetic Acid / Q000494:pharmacology; D005260:Female; D006801:Humans; D007558:Italy; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects; D010976:Platelet Count; D013921:Thrombocytopenia / Q000175:diagnosis / Q000453:epidemiology*
chemical_list: D004492:Edetic Acid