A-156 White Blood Cell Measurands, Flagging and Scatter Plot Patterns in Chronic Lymphocytic Leukemia
Authors: Silva S , Li Y , Chen Y , Ismail M , Musolino S , Talarico I , Cosseddu D , Montaruli B , Insana A , Rongey C 
Published: September 2023

Abstract

Background
In this study, we use Alinity hq hematology analyzer to investigate the differences between white blood cell measurands of a healthy control population vs Chronic Lymphocytic Leukemia (CLL). A repeatability study was also conducted to determine the precision of the white blood cell parameter results on the Alinity hq. In addition, we used Alinity hq to identify unique flagging and patterns in the optical channels for CLL.

Methods
One hundred and fifteen peripheral blood samples of CLL were compared to a population of four hundred and fourteen healthy controls on the Alinity hq analyzer. Statistical differences in Alinity hq’s white blood cell measurands compared between the control population and CLL. For the repeatability study, five CLL samples (with sufficient volume) will be tested in 10 replicates for WBC measurands. These samples can be part of the 115 samples above or can be different samples. Comparison of scatterplots were also analyzed between CLL and control samples. Lastly, a peripheral smear was performed on all CLL samples.

Results
Statistical analysis of the means of the white and red cell parameters showed that in comparison to the means of the control population there was a significant statistical (P &lt; 0.05) and clinical difference with CLL for the following parameters: absolute white blood cells (WBC) X 103/µL (43.6 CLL vs 7.41 control), percent neutrophils (%N) (18.25 CLL vs 53.71 control), percent lymphocytes (%L) (77.72 CLL vs 33.47 control), and percent monocytes (%M) (2.71 CLL vs 8.75 control). The WBC repeatability study results showed good concordance on the Alinity hq CBC + Diff + Retic test mode with the following percent coefficient of variance (%CV) results: absolute WBC X 103/µL (0.64, 5.31), percent neutrophils (%N) (1.32, 5.57), percent lymphocytes (%L) (0.20, 2.49), and percent monocytes (%M) (3.99, 26.39). As expected, the %CV range for monocytes is wide due to lymphocyte/variant lymphocyte population extending into the monocyte cluster. Evaluation of flagging showed 67 of the 115 (58.26%) CLL samples had a blast flag and 88 out of the 115 (76.52%) CLL samples had a variant lymphocyte flag. Review of the raw data from the optical channels shows a dominant and elongated lymphocyte cluster on the IAS, FL1 and PSS channels vs ALL for the CLL sample group compared to the control population. In the IAS and PSS vs ALL scatter plots in the CLL samples the lymphocyte cluster extends into the monocyte population triggering the blast flag. Peripheral smear review confirmed the presence of CLL (i.e., numerous smudge cells, mature-looking lymphocytes with characteristic condensed “soccer ball” pattern chromatin and scant cytoplasm) in the experimental group.

Conclusion
CLL is a cancer of the blood and bone marrow that predominately affects the quantity, and morphology of lymphocytes. Patients present with an abnormally high relative and variant lymphocyte populations. As such, there are a number of signs found in WBC measurands, flagging, and scatter plots on the Alinity hq that can be used as an early screening tool for CLL.