What is the average hemoglobin count for a 40-year-old woman?

A normal hemoglobin count for an adult woman is between 12 and 15.5 grams per deciliter, according to the Mayo Clinic. However, the range of normal levels may be slightly different depending on the doctor or laboratory.

A low hemoglobin count, meaning the body has a lower than normal amount of red blood cells, is called anemia and can be caused by nutritional shortages, loss of blood or kidney failure, says MedicineNet. A high hemoglobin count is often present in people who smoke or live in places with high altitude. Dehydration can also be a temporary cause of a high hemoglobin count. Rarer causes of high hemoglobin include lung disease and tumors.