Hereditary hemochromatosis is a genetic disorder that causes the body to absorb too much iron from the diet, leading to a buildup of the mineral over time. This excess iron is stored in various organs, which can eventually lead to tissue damage and organ failure if left untreated. Measuring the amount of iron stored in the body is a primary method for diagnosing and monitoring this condition. Ferritin, the main iron-storage protein, serves as a crucial indicator of this iron accumulation.
Ferritin’s Function in Iron Storage
Ferritin is a protein complex that acts as the body’s primary iron storage unit, sequestering iron atoms within a hollow spherical structure. It is found predominantly inside cells, particularly those in the liver, spleen, and bone marrow, where iron is managed and recycled. The protein ensures that iron is available for bodily functions while simultaneously preventing it from causing toxic damage through its reactive chemical nature.
A small amount of ferritin circulates in the blood, known as serum ferritin, which represents the body’s total iron reserves. In hemochromatosis, the body’s iron stores become excessively full, causing serum ferritin levels to climb significantly.
Interpreting this measurement can be complicated, however, because ferritin also functions as an acute-phase reactant. This means the protein can become elevated in response to inflammation, infection, or liver disease, even if the body’s true iron stores are not overloaded. Therefore, while a high ferritin level strongly suggests iron overload in the context of hemochromatosis, other markers of inflammation must also be considered for an accurate diagnosis.
Diagnostic Thresholds for Hemochromatosis
The levels of serum ferritin considered diagnostic for iron overload in hemochromatosis are clearly defined but differ based on biological sex. In general, a ferritin level exceeding 300 nanograms per milliliter (ng/mL) in men and postmenopausal women is highly suggestive of iron overload. For premenopausal women, the threshold is often lower, with levels above 200 ng/mL raising suspicion. This difference is primarily due to monthly blood loss through menstruation, which naturally lowers a woman’s iron stores.
High ferritin alone is rarely sufficient for a definitive diagnosis of hereditary hemochromatosis, and it must be evaluated alongside other blood tests. The most important companion test is the transferrin saturation (TSAT), which measures the percentage of transferrin saturated with iron. A consistently elevated TSAT, typically above 45%, is often the earliest laboratory sign of the disorder, occurring before ferritin levels become markedly high.
When both ferritin is elevated above the sex-specific thresholds and TSAT is high, the suspicion for hemochromatosis is strong enough to warrant genetic testing for mutations in the HFE gene. The combination of these two blood markers provides a robust picture of both the total stored iron (ferritin) and the amount of iron actively moving through the bloodstream (TSAT).
Ferritin Levels and Assessing Organ Damage
The height of the ferritin level provides crucial information about the severity and staging of the disease. Ferritin levels in very high ranges indicate a greater risk of iron deposition in organs. Specifically, a serum ferritin concentration exceeding 1,000 ng/mL is considered a signal for a higher risk of significant organ damage, particularly liver fibrosis or cirrhosis.
This extremely high level suggests the iron overload has reached a point where it is actively causing tissue harm, prompting a need for urgent therapeutic intervention. Patients presenting with ferritin above this 1,000 ng/mL mark, especially if they are over 40 years old, often require additional testing, such as a liver biopsy or specialized magnetic resonance imaging, to formally stage the extent of liver damage. The direct correlation between a ferritin level over 1,000 ng/mL and the risk of cirrhosis makes this number a powerful prognostic tool.
Treatment for hemochromatosis typically involves therapeutic phlebotomy to remove excess iron. The goal of this induction phase is to reduce the ferritin level significantly, often aiming for a level below 50 ng/mL, to reverse iron toxicity and prevent further organ damage. Once this target is reached, patients enter a maintenance phase, where physicians aim to keep the ferritin within a safe range, generally between 50 and 100 ng/mL, to prevent re-accumulation without causing iron deficiency.