What labs are included in an iron panel?

Iron Panel Components

A complete iron panel includes: serum iron, total iron binding capacity (TIBC), transferrin saturation (TSAT), and serum ferritin. 1

Core Components

The standard iron panel consists of the following tests:

• Serum iron: Measures the amount of circulating iron bound to transferrin 1

• Total iron binding capacity (TIBC): Measures the iron-binding capacity within serum and reflects the availability of iron-binding sites on transferrin 2

• Transferrin saturation (TSAT): Calculated by dividing serum iron by TIBC and multiplying by 100, expressed as a percentage 2

• Serum ferritin: An iron-storing protein that reflects total body iron stores 1

Additional Components in Comprehensive Evaluation

A full iron panel may also include:

• Complete blood count (CBC) with reticulocyte count, specifically examining hemoglobin, hematocrit, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and red blood cell distribution width (RDW) 1

• Transferrin concentration: Can be measured directly or calculated from TIBC 1

• Unsaturated iron binding capacity (UIBC): Represents the portion of transferrin not bound to iron; TIBC equals serum iron plus UIBC 2

Mathematical Relationships

The key calculation is: TSAT = (Serum Iron ÷ TIBC) × 100 2

Additionally: TIBC = Serum Iron + UIBC 2

Clinical Interpretation Framework

• Iron deficiency is indicated by low serum iron, elevated TIBC, low transferrin saturation (<20%), and low ferritin (<30 ng/mL in non-inflammatory states) 1, 3

• Ferritin is an acute-phase reactant and can be falsely elevated during illness, inflammation, or stress, potentially masking iron deficiency 1

• TSAT <16-20% in adults confirms iron deficiency 2, 3

Important Caveats

• Transferrin or TIBC measurement alone outperforms serum iron and saturation indices in predicting iron deficiency, with diagnostic accuracy of 0.94 compared to 0.77 for iron alone 4

• Several factors affect TSAT measurement including diurnal variation, recent meals, inflammation, and infection 2

• In iron overload conditions, UIBC may be decreased or near zero as transferrin becomes saturated 2