The correct term for high hemoglobin product is hematocrit, and its elevation may be related to physiological factors such as living environment, or pathological factors such as dehydration, congenital heart disease, and true erythrocytosis. 1. Physiological factors: daily life in higher altitude areas, due to the lower oxygen content in the air, resulting in an increase in the number of red blood cells and higher hemoglobin content, which may result in a high hematocrit. 2. Pathologic factors: (1) Dehydration: mainly caused by severe vomiting, severe diarrhea, etc., due to the loss of more water in the body, the blood is concentrated, which may lead to the appearance of hematocrit. (2) Congenital heart disease: mainly due to heredity, physical and chemical stimuli, etc. As the body is in a mild hypoxic state, the number of red blood cells increases compensatorily, which may lead to the appearance of high hematocrit. (3) True erythrocytosis: it is a myeloproliferative tumor with predominantly increased erythrocytes, which is mainly caused by genetic abnormality and may lead to high hematocrit. Therefore, when hematocrit is high, it is recommended to cooperate with doctors to improve relevant examinations to clarify the cause and then target treatment.