Causes of a low ferritin level include chronic bleeding in the digestive tract, heavy menstrual bleeding, iron-deficiency anemia and problems absorbing iron, explains MedlinePlus. Ferritin is a protein that stores iron in the body.
A normal ferritin level ranges from 12 to 150 nanograms per milliliter in women and 12 to 300 nanograms per milliliter in men, reports MedlinePlus. The ferritin blood test helps determine if there is enough iron stored in the body for later use. If a person's ferritin level reaches the low end of the normal range, it is likely she does not have enough iron.
The ferritin blood test is used to determine the cause of anemia symptoms, such as headaches, dizziness, weakness, pale skin and chronic fatigue, states Lab Tests Online. It is also used to check for iron overload in people suffering abdominal pain, fatigue, joint pain, weight loss or loss of body hair.
Iron plays an important role in oxygen transport, according to Washington University in St. Louis. Without iron, blood would not able to carry oxygen because there would be no way to bind molecular oxygen in the lungs and carry it to other parts of the body. Iron is also necessary for producing neurotransmitters, proteins and connective tissues.