A normal hemoglobin for adult females ranges from 12.1 to 15.1 grams per deciliter, according to MedlinePlus. Normal value ranges may differ slightly depending on the laboratory, sample and measurements used, so it's best to discuss individual results with a doctor.
Low hemoglobin levels may indicate various types of anemia, bleeding in the digestive tract, chronic kidney disease, poor nutrition or certain chronic illnesses, explains MedlinePlus. Hemoglobin may also be low if the bone marrow cannot produce new blood cells as a result of certain cancers, infections, bone marrow problems or drug toxicity. High hemoglobin levels are usually caused by the long-term lack of oxygen in the blood due to conditions such as severe lung problems, certain birth defects and right-sided heart failure.