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Iron and Iron-Binding Capacity

Iron and iron-binding capacity — assessment of blood iron level and transferrin saturation.

Panel including serum iron, total iron-binding capacity (TIBC), and transferrin saturation; used to evaluate iron deficiency and iron overload.

Indication

  • Symptoms of anemia such as fatigue, easy tiring, and pallor
  • Detection of low hemoglobin or low MCV on a complete blood count
  • Diagnosis and follow-up of iron deficiency anemia
  • Investigation of chronic bleeding (gastrointestinal, gynecological)
  • Suspicion of hemochromatosis (iron overload)
  • Differentiating anemia of chronic disease from iron deficiency anemia
  • Iron profile assessment during pregnancy

Preparation

  • Generally 8-10 hours of fasting is recommended; early morning blood draw is preferred
  • Iron supplements may be discontinued for a few days before the test with physician approval
  • Medications and vitamins being used should be reported to the physician
  • Recent blood transfusion should be reported
  • Acute infection or inflammation may affect the result

How it's performed

  1. A venous blood sample is collected from the arm (typically 3-5 mL)
  2. The blood is transferred into a biochemistry tube
  3. Serum iron, total iron-binding capacity (TIBC), and transferrin levels are measured on an automated analyzer
  4. Transferrin saturation (% TS) is calculated: serum iron / TIBC × 100
  5. Results are reported in standard units (μg/dL and %)

Post-procedure

  • Results are usually available the same day
  • When iron deficiency is detected, results are generally evaluated together with ferritin
  • If treatment is initiated, the physician may request a follow-up test after 1-3 months
  • Temporary tenderness at the blood draw site resolves on its own

Risks

  • Pain or bruising at the blood draw site (transient)
  • Rare small hematoma
  • Vasovagal reaction (dizziness, faintness; rare)
  • Very rarely, local infection at the needle site

FAQ

What does transferrin saturation mean?

It indicates the proportion of iron bound to its carrier protein, transferrin. A value below 20% generally suggests iron deficiency, while above 50% raises concern for iron overload.

Can I continue taking iron pills before the test?

Because iron supplements can temporarily raise serum iron levels, it is recommended to pause them for at least 24 hours before the test, or for the duration recommended by your physician.

My result shows low iron and high TIBC; what does this mean?

This combination is consistent with the classic pattern of iron deficiency anemia. For a definitive diagnosis, evaluation together with a ferritin test is helpful.

Is the iron test alone sufficient for iron deficiency?

It is not sufficient on its own. Evaluation of iron deficiency anemia requires interpreting ferritin, transferrin saturation, and complete blood count together.