It is an established fact that the average diameter of red blood cells in secondary anemia is decreased, and that many macrocytes are found in pernicious anemia. Occasionally there is difficulty in estimating the size of the cells by merely looking at the blood smear, especially if there is much distortion, or if the size and shape vary only slightly from normal. The exact measurement of the cells and the plotting of curves showing their distribution according to size may thus aid in the differentiation of anemias. My purpose was to find a practical and accurate method of measuring the diameter of the red blood cells.
Price-Jones1 and others made stained films of blood, projected the image on to a sheet of paper, then measured the minimum and maximum diameters, and used the average as the diameter of the cell. In each film 500 cells were measured.
Grosh and Stifel2
McCORMICK AR. THE DIAMETER OF RED BLOOD CELLS IN HEALTH AND IN ANEMIA: A NEW METHOD OF MEASUREMENT. Arch Intern Med (Chic). 1927;39(6):799–807. doi:10.1001/archinte.1927.00130060051004
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