Davis's Lab & Diagnostic Tests
Iron StudiesIron (Total), Iron-Binding Capacity (Total), Transferrin, and Iron Saturation
General
Synonym/Acronym:
iron: Fe; iron-binding capacity and iron saturation: TIBC, Fe Sat; transferrin: siderophilin, TRF.
Rationale
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.
| Iron | |||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Age | Conventional Units | SI Units (Conventional Units × 0.179) | |||||||||||||||||||||||||||||||||||||||
| Newborn | 100–250 ug/dL | 17.9–44.8 micromol/L | |||||||||||||||||||||||||||||||||||||||
| Infant | 40–105 ug/dL | 7.2–18.8 micromol/L | |||||||||||||||||||||||||||||||||||||||
| Child | 50–120 ug/mL | 9–21.5 micromol/L | |||||||||||||||||||||||||||||||||||||||
| 11 yr–adult | |||||||||||||||||||||||||||||||||||||||||
| Male | 45–182 ug/dL | 8.1–32.6 micromol/L | |||||||||||||||||||||||||||||||||||||||
| Female | 28–170 ug/dL | 5–30.4 micromol/L | |||||||||||||||||||||||||||||||||||||||
| Values tend to decrease in older adults. | |||||||||||||||||||||||||||||||||||||||||
| Test | Conventional Units | SI Units (Conventional Units × 0.179) | |||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| TIBC | 250–450 mcg/dL | 45–81 micromol/L | |||||||||||||||||||||||||||||||||||||||
| Transferrin-iron saturation % | 20%–50% | 20%–50% | |||||||||||||||||||||||||||||||||||||||
| Conventional Units | SI Units (Conventional Units × 0.01) | ||||||||||||||||||||||||||||||||||||||||
| Transferrin (direct measurement) | 200–360 mg/dL | 2–3.6 g/L | |||||||||||||||||||||||||||||||||||||||
| The percentage of transferrin saturated with iron can be calculated as either (serum iron/TIBC value) × 100 or (serum iron × 100%)/TIBC. | |||||||||||||||||||||||||||||||||||||||||
Critical Findings and Potential Interventions
Iron
- 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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