Iron Panel Components
A full iron panel includes: complete blood count with reticulocyte count (specifically hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, red blood cell distribution width), ferritin, serum iron, transferrin, transferrin saturation, and total iron binding capacity. 1
Core Components
Complete Blood Count (CBC) with Reticulocyte Count
- Hemoglobin - measures oxygen-carrying capacity and defines anemia (WHO criteria: <12 g/dL in females, <13 g/dL in males) 1
- Hematocrit - percentage of blood volume occupied by red blood cells 1
- Mean Corpuscular Volume (MCV) - average red blood cell size 1
- Mean Corpuscular Hemoglobin (MCH) - average hemoglobin content per red blood cell 1
- Mean Corpuscular Hemoglobin Concentration (MCHC) - average hemoglobin concentration in red blood cells 1
- Red Blood Cell Distribution Width (RDW) - variation in red blood cell size 1
- Reticulocyte count - measures bone marrow's red blood cell production 1
Iron-Specific Markers
- Serum iron - measures circulating iron using colorimetric reaction with chromagen (no universal reference ranges exist) 1
- Ferritin - iron storage protein with reference intervals of 20-250 μg/L in men and 20-200 μg/L in women 1
- Transferrin - iron transport protein 1
- Transferrin saturation (TSAT) - ratio of serum iron to total iron binding capacity expressed as percentage; should be <15% in true iron deficiency 2
- Total Iron Binding Capacity (TIBC) - measures blood's capacity to bind iron with transferrin 1
Critical Interpretation Pitfalls
Ferritin is an acute-phase reactant and can be falsely elevated during illness or stress, masking iron deficiency. 1 This is why a single ferritin value is insufficient for diagnosis and the complete panel is necessary.
Advanced Markers (When Basic Panel is Inconclusive)
- Reticulocyte hemoglobin content (CHr) - reflects iron available in bone marrow for erythropoiesis; readily available on most hematology analyzers 1
- Soluble transferrin receptor (sTfR) - helpful when ferritin and transferrin saturation are inconclusive 1
- Hepcidin - analyzed using ultra-high-pressure chromatography; may prove most precise for diagnosing deficiency in inflammatory conditions but not yet widely available 1
- Zinc protoporphyrin - newer method for assessing iron status 1
Gold Standard Confirmation
When results remain unclear and definitive diagnosis is critical, bone marrow biopsy showing lack of stainable iron remains the gold standard for diagnosing iron deficiency. 1