The Measurement of Red Cell Size in Peripheral Blood Smear:Comparison of Mean Corpuscular Area and Mean Corpuscular Volume

Kim, Hyun Soo; Ko, Hak Hyun; Lee, Do Hoon

Abstract

BACKGROUND
We intended to investigate the relationship between red cell size observed through a light microscope and mean corpuscular volume (MCV) measured by an automatic hematology analyzer.
METHODS
164 samples which were referred for complete blood count analysis and peripheral blood cell morphology were selected. MCV was measured by Gen-S (Coulter Co., USA). Smear slides of the same samples were examined on a microscope with a CCD camera connected to it. The image observed through the microscope emerged on an IBM-compatible computer system through the CCD camera. Mean red cell size-mean corpuscular area (MCA) of the captured image was calculated by Image-Pro Plus, the image capture and analyzing software.
RESULTS
The coefficient of variation (CV) of MCA measurement, which was done 5 times on 10 slides, was 1.5-3.6%. Compared to the measurements performed in the ideal zone, MCA was measured lower in the thickly smeared zone (medial zone) and higher in the thinly smeared zone (lateral zone) on smear slide observation. The correlation between MCA and MCV values was poor (R=0.641, P<0.01). The normal reference range of MCA measurement was 37.40-50.22 m2.
CONCLUSIONS
As the red cell size observed on the light microscope does not correlate well with the MCV measured by automatic analyzer, the determination of red cell size by microscopic peripheral blood smear requires profound caution.