WHAT ELEVATED IRON COULD SIGNAL
A 34-year-old, healthy, African-American man with no chronic medical problems is found to have a high serum iron level (266 µg/dL, normal: 40-155) along with normal aspartate aminotransferase, alanine aminotransferase, and g-glutamyltransferase levels. The patient does not take any OTC or herbal medications, iron supplements, or vitamins. Given the normal liver enzyme levels, hemochromatosis seems unlikely. What other diagnoses should be considered?
—Davina Dansby, MD, Stone Mountain, Ga.
Plasma iron levels should be interpreted in the context of other iron studies, especially ferritin levels and transferrin saturation (the ratio of plasma iron to transferrin). These measures are more sensitive for diagnosing iron overload states, such as hemochromatosis. Hereditary hemochromatosis (HH) should be considered if the fasting transferrin saturation is >60% in men or >50% in women, even if the liver function tests are normal. The fasting transferrin saturation should be used because plasma iron levels vary throughout the day and can differ by as much as 30% on a day-to-day basis.
After you have ruled out primary iron overload due to HH (which can be done with genetic testing), diagnoses that should be considered in secondary iron overload include chronic liver disease (due to hepatitis C or alcohol or fatty liver), iron-loading anemias (such as thalassemia, sideroblastic anemia, chronic hemolytic anemia, or lead poisoning), or iron overload due to transfusions or dietary iron overload.
—Susan Kashaf, MD, MPH (111-14)