Hemoglobin 103g/L is abnormal and belongs to mild anemia because the normal range of hemoglobin is 120-160g/L for adult males and 110-150g/L for adult females, so hemoglobin 103g/L is mild anemia. Clinically, hemoglobin 103g/L can be seen in a variety of diseases, such as mild iron deficiency anemia, mild megaloblastic anemia, certain chronic aplastic anemia, etc. These patients can have a hemoglobin of 103g/L. Routine blood tests, combined with average red blood cell volume red blood cell average, average red blood cell hemoglobin volume and average red blood cell hemoglobin concentration, can often make a general determination of the cause of anemia. If a patient has a hemoglobin of 103g/L with a decrease in mean red blood cell volume, mean red blood cell hemoglobin volume, and mean red blood cell hemoglobin concentration, the patient is most likely to have iron deficiency anemia. If the patient has a hemoglobin of 103 g/L with an abnormally high mean erythrocyte volume and mean erythrocyte hemoglobin volume, the most likely cause is megaloblastic anemia.