Determination of the Number of Erythrocytes

By JAVIER ROBLES GIL, M.D., AND DIEGO GONZALEZ TERAN, M.D. T HIS work is a contribution to the knowledge of certain hematologic standards among a group of healthy residents of Mexico City. The standards studied are volume of packed red cells, hemoglobin in grams per ioo cc. of blood, red blood cell count, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, mean corpuscular diameter, mean corpuscular thickness and sedimentation rate. Hedin and Blix in 1.890 and Daland’ in 1891 were the first investigators to introduce the use of the hematocrit, that is, the determination by special procedures of the volume of packed red cells in a given amount of blood. Chapin,3 Millar,4 Kennedy and Millikan’ and Ponder and Saslow6 believe there exists a 2. to 12. per cent factor of error in the determination of the hematocrit. They found this factor of error when measuring the cell volume by means of other procedures, such as those that include the use of dyes, proteins and tagged erythrocytes containing radioactive iron. But this factor of error, if it exists, does not invalidate the procedure for practical purposes. The standards investigated in this work are probably of definite value in the study of the anemias. They give a clearer idea of the extent to which one of the most important functions of the blood, hematosis or blood oxygenation, is modified. The red cell count alone does not give sufficient information concerning this function, since there may exist microcytosis or hypochromia or both. Furthermore, the mean corpuscular volume and the mean corpuscular hemoglobin concentration cannot be determined when only the red cell count and the hemoglobin, without the volume of packed red cells, are known. The results obtained by different investigators are in agreement with the fact that the hematologic standards are the same for all races and economic levels.7’6 Changes due to age and sex have also been established. Smith et al.,’7 Licknatzky,’8 Acton and Harvey,’9 Haden,’#{176} Horneffer,” Barcroft et Cordero,’3 Vergara Lope,’4 Ocaranza,’5 Izquierdo’6 and others found an increase in the number of erythrocytes associated with an increase in the altitude. Licknatzky’8 and Fitzgerald’7 observed an increase of hemoglobin in the same conditions. Hurtado’8’ ‘9 and Andresen et al.3#{176} found that the mean corpuscular volume is greater at high altitudes than at sea level. Other climatic factors have no influence, as Walters,3’ Wintrobe32’ #{176} and Myers and Eddy’3 have shown in their works.