Leucocytes Identified by Automated Digital Morphology System

An automated digital cell morphology analyzer for determining leukocyte differential counts in peripheral blood smears (PBS) has been evaluated in a clinical laboratory.

The differential counting of peripheral blood leukocytes is one of the most frequently ordered laboratory tests by clinicians as it is an important test for the diagnosis of various hematologic diseases and systemic diseases. Improvements in laboratory technologies have benefited from the development of automated blood cell counters that have begun to replace the manual microscopic counting that is still performed in most laboratories.

Laboratory scientists at the University of Ulsan College of Medicine and Asan Medical Center (Seoul, Republic of Korea) examined a total of 308 peripheral blood samples with quantitative or qualitative abnormalities, for which complete blood counts had been ordered by clinicians. These samples were initially analyzed using the automatic blood cell analyzer Sysmex XE-2100 (Sysmex; Kobe, Japan), and the total leukocyte and differential counts were determined. Manual microscopic differential counts of 100 cells on each slide were separately performed by two independent well-trained laboratory technologists.

The slides were labeled and loaded into the CellaVision DM96 system (CellaVision AB; Lund, Sweden) after manual microscopic differential counting. In cases with a buffy coat preparation, the slides were prepared using samples prior to buffy coat preparation and labeled in the CellaVision DM96 system To evaluate the clinical relevance of the extension of cell counts up to 300 or 500 cells, which is the provided function by the CellaVision DM96 system, in the samples with low leukocyte count of less than 1,000 cells/μL, correlation analysis between the CellaVision DM96 system and manual count was performed.

The correlation coefficients between two methods were consistently high, ranged from 0.864 to 0.992. The sensitivity, specificity, positive predictive value, negative predictive values of this system for the identification of abnormalities was consistently high, especially for blast cells. When the instrument was instructed to count 300 or 500 cells from the operator, better performance was demonstrated than 100 cells in the leukopenic samples by sacrificing only 40 seconds/slide on average.

The authors concluded that the CellaVision DM96 system is useful in the clinical laboratory providing comparative accuracy compared with manual counts in samples with abnormalities. In leukopenic samples, report quality can be improved by ordering to count 300 or 500 cells from the operator without severe prolongation of turnaround time. The study was published on the October 2013 issue of the International Journal of Laboratory Hematology .

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University of Ulsan College of Medicine and Asan Medical Center
Sysmex 
CellaVision AB