A hemoglobin concentration of 166 g/L is abnormal and slightly higher than the normal range. The normal range of hemoglobin concentration is 120-160 g/L for adult males and 110-150 g/L for adult females, so the patient’s hemoglobin concentration of 166 g/L is slightly higher than the normal range. There are physiological and pathologic reasons for high hemoglobin concentration. 1. Physiological causes: can be seen in residents living in the plateau. 2. Pathologic causes: can be seen in true erythrocytosis, as well as chronic heart failure, chronic obstructive pulmonary disease hypoxia. When there is a lot of sweating and vomiting, high hemoglobin concentration can occur due to blood concentration. When patients find that the examination suggests a hemoglobin concentration of 166, it is recommended that they consult their doctors in time to see if further examination is needed, and carry out the appropriate treatment after a clear diagnosis, rather than interpreting on their own and ignoring it easily.