The presence and severity of anemia can be identified by testing a blood sample to assess hemoglobin levels. Hemoglobin is a type of protein that is part of the red blood cells, so the presence of this protein is indicative of the number of red blood cells present in the blood sample. Low quantities of red blood cells will cause the hemoglobin levels to diminish as well, so if a patient is suffering from a condition such as anemia or cancer, their blood sample would show a low level of hemoglobin. A normal hemoglobin level can vary a bit depending on gender, with a normal range for females being between 12.3 gm/dL and 15.3 gm/dL and for males being between 14.0 grams per deciliter (gm/dL) and 17.5 gm/dL. A hemoglobin level that is considered severely low for females would be at or lower than 12 gm/dL and for males, it would be at or lower than 13.5 gm/dL.