Serum Iron (Iron)
Serum iron measures the concentration of ferric (Fe3+) iron bound to circulating transferrin in plasma, displaying a prominent diurnal variation with peak levels in the morning.
Standard vs. Optimal Reference Rangesμg/dL
Standard reference intervals represent the statistical 95% distribution of unselected commercial populations. Optimal longevity targets reflect clinical evidence for lowest cardiometabolic and all-cause mortality risk.
Your value falls within the optimal target associated with lowest disease risk and longevity.
60 - 170 μg/dL (Male), 50 - 160 μg/dL (Female)
General reference distribution across unselected commercial populations.
75 - 130 μg/dL
Concentration target associated with minimal all-cause cardiometabolic mortality.
Molecular Mechanism & Clinical Purpose
Iron released from reticuloendothelial macrophage recycling of senescent erythrocytes (20-25 mg daily) and enterocyte absorption (1-2 mg daily) is loaded onto transferrin for delivery to erythroid bone marrow.
Differential Diagnosis
Elevated Levels (Iron High)
- •Iron overload syndromes / Hemochromatosis
- •Acute iron toxicity / Supplementation
- •Hemolytic anemias / Ineffective erythropoiesis
- •Acute hepatic parenchymal necrosis
Low Levels (Iron Low)
- •Iron deficiency states
- •Acute or chronic systemic inflammation (hepcidin-mediated iron sequestration)
- •Hypothyroidism
Technical Reference & Deep Dive
Biochemistry & Enzymatic Pathways
Longevity Risk Architecture & Epidemiology
Pre-Analytical Caveats & Diagnostic Workup
Pre-Analytical Considerations:
Venipuncture must be performed in the morning (between 7:00 AM and 10:00 AM) due to pronounced diurnal variation in circulating iron levels. A 12-hour overnight fast is required; avoid oral iron supplements for at least 24 to 48 hours prior to testing. Ferritin is an acute-phase reactant; measure concurrent hs-CRP to rule out falsely elevated ferritin from systemic inflammation or acute infection.
Reflexive Testing Protocol:
- Complete Iron Panel (Serum Iron, Total Iron-Binding Capacity, Ferritin, Transferrin Saturation Percentage)
- Soluble Transferrin Receptor (sTfR) and sTfR-Ferritin Index to differentiate iron deficiency anemia from anemia of chronic disease
- HFE Gene Mutation Analysis (C282Y, H63D) to screen for hereditary hemochromatosis in cases of persistent transferrin supersaturation
- High-sensitivity C-Reactive Protein (hs-CRP) and Erythrocyte Sedimentation Rate (ESR) to evaluate inflammatory status
- Upper and lower endoscopy (EGD and Colonoscopy) to rule out occult gastrointestinal blood loss in unexplained iron deficiency
Clinical Citations & Primary Literature (1)
- [1]Systemic Iron Homeostasis and the Hepcidin-Ferroportin Axis - Nature Reviews Endocrinology (2021). PMID: 34188735
Associated Longevity Guides & Clinical Calculators
Medicine 3.0Explore comprehensive evidence-based clinical protocols, testing costs, and algorithmic calculators that incorporate Serum Iron (Iron) into overall healthspan optimization.