Pseudoplatelets: a retrospective study of their incidence and interference with platelet counting.
OBJECTIVE
Spurious platelet counts can be found in acute leukaemias, as a result of the fragmentation of blood cells. Microscopic examination of a blood smear should be performed to detect the presence of these so called pseudoplatelets. When present, the platelet count should be corrected because of the important clinical consequences that a lower platelet count may have in these patients.


METHODS
K(3)EDTA anticoagulated blood was measured on an automated blood cell counter, and a blood smear was made and stained according the May Grünwald-Giemsa method for microscopic observation. A 500 cell/particle differentiation was performed and the automated platelet count was corrected.


RESULTS
The incidence of pseudoplatelets in 169 patients with acute leukaemia was studied. Pseudoplatelets were detected in 43 patients (25.4%), and seven patients (4.1%) were re-classified as having a major bleeding risk (platelet count, < 15 x 10(9)/litre).


CONCLUSIONS
Platelets should be determined morphologically in patients with acute leukaemia and a routine screening method for the detection of pseudoplatelets should be developed.
D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001773:Blood Cells / Q000473:pathology*; D002648:Child; D005260:Female; D006801:Humans; D007951:Leukemia, Myeloid / Q000097:blood; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000097:blood*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013347:Subcellular Fractions