Ethylenediaminetetraacetate-dependent pseudothrombocytopenia accompanied by morphological changes

Abstract

A 65-year-old female patient was referred to our hospital for diabetes mellitus, diabetic nephropathy, pulmonary infection, and hypertension on November 6, 2012. Following admission, findings from laboratory tests were as follows: white blood cell count, 14.76 9 10/L; hemoglobin, 123 g/L; platelet count, 28 9 10/L; creatinine, 272 lmol/L; fasting glucose, 14.26 mmol/L; prothrombin time, 14.6 s; D-dimer, 4800 lg/L. Tests for antinuclear and antineutrophil cytoplasmic antibodies were negative, but were positive for platelet-associated IgG. Dipotassium EDTA, sodium citrate, and heparin sodium were selected as the anticoagulants for blood cell counts, to exclude the influence of EDTA salt. We performed whole-blood cell counts measured by a Sysmex XE-2100 complete blood count analyzer, followed by blood smears and staining with a Sysmex sp1000i automated hematology slide preparation unit. The platelet and white blood cell counts were 12 9 10 and 6.9 9 10/L for EDTA-2K anticoagulants, 242 9 10 and 4.3 9 10/L for sodium citrate anticoagulants, 250 9 10 and 4.6 9 10/L for heparin sodium anticoagulants, respectively. The blood smear results are shown in Figs. 1 and 2. The International Committee for Standardization in Hematology recommends dipotassium EDTA for anticoagulation of peripheral blood cells for analysis [1]. Blood specimens that met the review criteria after detection by the blood cell analyzer were smeared, stained, and observed under a microscope. When the platelet aggregation occurred, a cluster of platelets with uneven sizes was observed. However, the aggregated platelets retained their individual morphologies (Fig. 3). Microscopic examination of the blood smear revealed clumps of violescent material