Classification of the Anemias on the Basis of Differences in the Size and Hemoglobin Content of the Red Corpuscles.

Abstract

From determinations of the number of red corpuscles, the quantity of hemoglobin, and the relative volume of packed red cells in any sample of blood it is possible to calculate the mean volume and the hemoglobin content of the red corpuscles of the sample. 1 The constants derived by these calculations are spoken of as mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular concentration. Mean corpuscular volume is expressed in cubic microns. Mean corpuscular hemoglobin refers to the actual amount of hemoglobin contained in the average red corpuscle and is expressed in micromicrograms. Mean corpuscular concentration refers to the hemoglobin contained in the red corpuscle in proportion to its volume. In the determination of this constant the red corpuscle is presumed to contain an aqueous solution of hemoglobin the concentration of which is calculated and expressed in per cent.

Some 400 accurate blood determinations have been carried out in 140 patients suffering from anemia produced by a large variety of causes. On the basis of differences in the size and hemoglobin content of the red corpuscles observed in these cases, 4 distinct classes have been differentiated:

I. The first and most obvious group, which can be called macrocytic, includes the cases of pernicious anemia, sprue, and a case of pernicious anemia of pregnancy. The noteworthy characteristic of this group is an increase in the mean size and hemoglobin content of the red corpuscles. The increases in corpuscular volume and in corpuscular hemoglobin are proportional and thus the normal hemoglobin concentration of the cells is not disturbed. The increases in size and hemoglobin content vary more or less inversely with the red cell count but this correlation is not entirely stict. 2