Measurement of the depolarized orthogonal light scattering in flow cytometry enables one to discriminate human eosinephilic granulocytes from neutrophilic granulocytes. We use this method to perform a four-parameter differential white blood cell analysis. A simple flow cytometer was built equipped with a 5-mW helium neon laser that measures simultaneously four light scattering parameters. Lymphocytes, monocytes, and granulocytes were identified by simultaneously measuring the light scattering intensity at angles between 1.0° and 2.6° and angles between 3.0° and 11.0°. Eosinophilic granulocytes were distinguished from neutrophilic granulocytes by simultaneous measurement of the orthogonal and depolarized orthogonal light scattering. Comparison of a white blood cell differentiation of 45 donors obtained by the Technicon H-6000 and our instrument revealed good correlations. The correlation coefficients (r2) found were: 0.99 for lymphocytes, 0.76 for monocytes, 0.99 for neutrophilic granulocytes, and 0.98 for eosinophilic granulocytes. The results demonstrate that reliable white blood cell differentiation of the four most clinically relevant leukocytes can be obtained by measurement of light scattering properties of unstained leukocytes.
- Flow cytometry
- Differential leukocyte counting