Spurious platelet counts in acute leukaemia with DIC due to cell fragmentation.
Automated platelet counts in a patient with newly diagnosed AML M5 with extreme leukocytosis were reported as 129, 166 and 121 x 10(9)/1. Routine blood films showed a corresponding number of platelet-sized particles, judged to be platelets. The patient was treated for DIC with low-dose heparin infusion. Platelet transfusions were not given initially. The patient died 14 h after admission from intracerebral haematoma. The origin of the platelet-sized particles seen in routine stained blood films was examined by cytochemical and immunological staining for peroxidase, non-specific esterase, CD 13 and CD 33. About 1/3 of the fragments had the same staining characteristics as the leukaemia cells, indicating leukaemia cell origin. Staining for platelet-specific antigen GpIIIa was positive only in 4% of the platelet-sized fragments, with a calculated true platelet count of 4 x 10(9)/1. The presence of cell fragments masquerading as platelets should be suspected in leukaemia patients with bleeding symptoms and normal or near normal platelet counts.
Hammerstrøm
J
J
Department of Medicine, University Hospital of Trondheim, Norway.
D000208:Acute Disease; D016477:Artifacts; D001331:Automation; D004211:Disseminated Intravascular Coagulation / Q000097:blood* / Q000150:complications; D006801:Humans; D007951:Leukemia, Myeloid / Q000097:blood* / Q000150:complications; D008297:Male; D008875:Middle Aged; D010976:Platelet Count / Q000379:methods*