Bioingeniøren (Jan 2017)
Comparison of three different methods for identification of platelet clumps for assessment of thrombocytopenia
Abstract
When a patient’s platelet count is low, the sample is assessed for platelet clumps to distinguish between thrombocytopenia and pseudothrombocytopenia. Microscopic examination of blood smear is the standard method for identifying platelet clumps at Diakonhjemmet Hospital AS, but the method is time-consuming and may be challenging due to artefacts. The purpose of this project was to evaluate if two alternative methods, direct microscopic examination of EDTA whole blood and buffy coat, were suitable for identification of platelet clumps. In addition, the samples were analyzed by Sysmex XE-5000 before and after removal of 10 uL buffycoat, to investigate if platelet and leukocyte parameters were influenced to an extent that supplementary analysis after removal would not be possible. We included 57 samples with platelet counts lower than 90 x 109/L. Microscopic examination of buffy coat had a sensitivity of 97 % when compared to blood smear. In addition, the method was time-saving and easier to perform. Direct microscopic examination of whole blood was the easiest method to perform and most time-saving. However, the sensitivity was 64 % when compared to blood smear, and detecting possible platelets clumps was challenging due to the amount of erythrocytes present. Based on this, we do not recommended whole blood as an alternative method for identifying platelet clumps. Furthermore, the results show that there was no statistically significant difference in platelet and leukocyte parameters before and after removal of buffy coat. In addition, the observed difference in percent was less than the analytical variation, which indicates that the differences are of no clinical significance. We conclude that buffy coat may be used as an alternative method to blood smear to identify platelet clumps.
