A red blood cell 5.22 x 10^12/L is within the normal range for males, infants and children, and slightly high for adult females. The normal reference values for red blood cell count are: male (4.5-5.5) x 10^12/L, female (4.0-5.0) x 10^12/L, infant (6.0-7.0) x 10^12/L, and child (4.2-5.2) x 10^12/L. Therefore, a red blood cell count of 5.22 x 10^12/L is normal if it is for a male, an infant, and a child, and slightly high if it is for an adult females is slightly high. Causes of increased red blood cell count can be seen in non-disease causes such as strenuous exercise, emotional stress, long-term smoking, but also in vomiting, diarrhea, dehydration, extensive burns, true erythrocytosis, anemia, COPD, congenital heart disease, etc., which need to be clearly diagnosed in combination with other test results. Erythrocyte 5.22×10^12/L is mildly high in female patients. It is recommended to consult a doctor for a clear diagnosis based on symptoms and other tests.