Iron Studies: Iron (Total), Iron-Binding Capacity (Total), Transferrin, and Iron Saturation



Iron: Fe; iron-binding capacity and iron saturation: TIBC, Fe Sat; transferrin: siderophilin, TRF.


To monitor and assess iron levels related to blood loss, dietary intake and metabolism, storage disorders, and replacement therapy. To assist in diagnosing types of anemia such as iron deficiency.

Patient Preparation

Instruct the patient to fast for at least 12 hr before specimen collection for iron or transferrin and, with medical direction, to refrain from taking iron-containing medicines before specimen collection. There are no food, fluid, activity, or medication restrictions unless by medical direction for the TIBC and iron saturation. Specimen collection for iron studies should be delayed for several days after blood transfusion. Protocols may vary among facilities.

Normal Findings

Method: Spectrophotometry for iron and TIBC; nephelometry for transferrin.

AgeConventional UnitsSI Units (Conventional Units × 0.179)
Newborn100–250 mcg/dL17.9–44.8 micromol/L
Infant–14 yr40–105 mcg/dL7.2–18.8 micromol/L
15 yr–Adult
  Male75–175 mcg/dL13.4–31.3 micromol/L
  Female60–160 mcg/dL11–29 micromol/L
Values tend to decrease in older adults.
TestConventional UnitsSI Units (Conventional Units × 0.179)
TIBC250–450 mcg/dL45–81 micromol/L
Transferrin-iron saturation %15%–50%15%–50%
The percentage of transferrin saturated with iron can be calculated as either (serum iron/TIBC value) × 100 or (serum iron × 100%)/TIBC.
Transferrin (Direct Measurement)
AgeConventional UnitsSI Units (Conventional Units × 0.01)
Newborn130–275 mg/dL1.3–2.75 g/L
Infant–14 yr180–330 mg/dL1.8–3.3 g/L
15 yr–Adult
  Male215–365 mg/dL2.2–3.6 g/L
  Female250–380 mg/dL2.5–3.8 g/L

Critical Findings and Potential Interventions


  • Mild Toxicity: Greater than 350 mcg/dL (SI: Greater than 62.6 micromol/L)
  • Serious Toxicity: Greater than 400 mcg/dL (SI: Greater than 71.6 micromol/L)
  • Lethal: Greater than 1,000 mcg/dL (SI: Greater than 179 micromol/L)

Timely notification to the requesting health-care provider (HCP) of any critical findings and related symptoms is a role expectation of the professional nurse. A listing of these findings varies among facilities.

Intervention may include chelation therapy by administration of deferoxamine mesylate (Desferal).

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