High total erythrocyte count can be seen in relative erythrocytosis and absolute erythrocytosis. Relative erythrocytosis is mainly due to a decrease in plasma volume, which is a relative increase in red blood cell volume and blood concentration, and is seen in massive sweating, continuous vomiting, recurrent diarrhea, massive burns, diabetic ketoacidosis, and uremia. Absolute erythropoiesis, which can be divided into secondary and primary. Secondary erythropoietin increase in the blood, primary i.e. true erythropoietin. Secondary physiological increase, seen in newborns, alpine inhabitants, mountain climbers and heavy laborers, due to compensatory increase of erythropoietin from hypoxia. Pathologic increase, seen in obstructive emphysema, pulmonary heart disease, cyanotic congenital heart disease, due to chronic hypoxia, and also in certain tumors. Primary erythropoiesis, mainly true erythropoiesis, is characterized by a persistent and significant increase in red blood cells and an increase in total systemic blood volume, along with varying degrees of increase in white blood cells and platelets.