A case of EDTA-dependent pseudothrombocytopenia: simple recognition of an underdiagnosed and misleading phenomenon

Abstract

BackgroundEDTA-dependent pseudothrombocytopenia (EDTA-PTCP) is a common laboratory phenomenon with a prevalence ranging from 0.1-2% in hospitalized patients to 15-17% in outpatients evaluated for isolated thrombocytopenia. Despite its harmlessness, EDTA-PTCP frequently leads to time-consuming, costly and even invasive diagnostic investigations. EDTA-PTCP is often overlooked because blood smears are not evaluated visually in routine practice and histograms as well as warning flags of hematology analyzers are not interpreted correctly. Nonetheless, EDTA-PTCP may be diagnosed easily even by general practitioners without any experiences in blood film examinations. This is the first report illustrating the typical patterns of a platelet (PLT) and white blood cell (WBC) histograms of hematology analyzers.Case presentationA 37-year-old female patient of Caucasian origin was referred with suspected acute leukemia and the crew of the emergency unit arranged extensive investigations for work-up. However, examination of EDTA blood sample revealed atypical lymphocytes and an isolated thrombocytopenia together with typical patterns of WBC and PLT histograms: a serrated curve of the platelet histogram and a peculiar peak on the left side of the WBC histogram. EDTA-PTCP was confirmed by a normal platelet count when examining citrated blood.ConclusionAwareness of typical PLT and WBC patterns may alert to the presence of EDTA-PTCP in routine laboratory practice helping to avoid unnecessary investigations and over-treatment.

Ethylenediaminetetraacetic acid-dependent pseudothrombocytopenia in complex cardiac surgery

“…However, some other anticoagulants such as heparin, oxalate, hirudin, citrate, or abciximab may also cause pseudothrombocytopenia, although their actual incidence is still unclear. [5] The underlying mechanism of platelet clumping in pseudothrombocytopenia includes an immunological process which was first described by Shreiner and Bell in 1973. [6] The authors proved that EDTA caused a new type of platelet agglutinin, which was active at 37 °C, as well as at room temperature.…”

“…The prevalence of EDTAdependent pseudothrombocytopenia is reported to be between 0.1% and 2% among hospitalized patients and up to 17% in patients with isolated thrombocytopenia. [3,5] The EDTA is an anticoagulant, which is frequently used for hematological tests, and may induce platelet clumping. However, some other anticoagulants such as heparin, oxalate, hirudin, citrate, or abciximab may also cause pseudothrombocytopenia, although their actual incidence is still unclear.…”

“…In addition, pregnant women and healthy individuals may rarely present with this disorder. [5] The diagnosis of pseudothrombocytopenia is of unique clinical importance to avoid a delay in surgery and unnecessary blood transfusion in patients undergoing cardiac surgery.…”

“…Pseudothrombocytopenia is only an in vitro effect, which does not cause any hemostatic complications, as all platelet functions and coagulation tests are normal. [5] It can be seen in some patients with autoimmune diseases, malignancies, chronic liver diseases, viral infections, and cardiovascular diseases. In addition, pregnant women and healthy individuals may rarely present with this disorder.…”

“…In addition, pregnant women and healthy individuals may rarely present with this disorder. [5] The diagnosis of pseudothrombocytopenia is of unique clinical importance to avoid a delay in surgery and unnecessary blood transfusion in patients undergoing cardiac surgery.Although EDTA-dependent pseudothrombocytopenia has been previously described in patients undergoing cardiac surgery, [2][3][4] its clinical features and management approaches still remain controversial for cardiac surgeons. Herein, we present a case of pseudothrombocytopenia who underwent aortic root replacement, mitral valve replacement, and tricuspid valve repair and discuss perioperative management of this entity.…”