TIBC (Total Iron Binding Capacity) Test

TIBC test measures the transferrin protein’s iron binding and carriage capacity. TIBC means total iron binding capacity or transferrin iron binding capacity. TIBC test is done to determine the iron deficiency and iron overload to find the cause of symptoms. TIBC  test also provides information about liver functions and it can be calculated by the determination of blood UIBC (unsaturated iron binding capacity)  and iron levels.


TIBC determines the total iron  amount that is carried by proteins. Almost all of the blood iron is carried by transferrin so TIBC amount shows the transferrin amount. TIBC is equal to the sum of UIBC and blood iron. UIBC provides information about the portion of the transferrin that is not bound to iron , this means the reserve capacity of transferrin that can carry iron. UIBC means unsaturated iron binding capacity because this reserved amount is not saturated and bound with iron. UIBC may be measured directly and also its value may be found by substracting serum iron from TIBC result.

How the TIBC test is performed?

A blood sample is needed, this means a needle will be inserted in a vein inside your elbow or on the back of your hand. One or more tubes of blood will be drawn according to the number of your tests. All blood collection process takes 1-2 minutes and you may feel a little pain for a few seconds.  TIBC test is done after fasting for 8-12 hours. Some medicines may affect your TIBC test result like;

Birth control pills



ACTH ( adrenocorticotropic hormone)

Purpose; why the TIBC test is done?

If you have symptoms of iron deficiency or iron overload your doctor requests TIBC test. This test is commonly requested with serum iron test and CBC/hemogram (complete blood count).

Iron deficiency symptoms


  • Tiredness
  • WeaknessTIBC UIBC
  • Chronic fatigue
  • Pale skin
  • Headache
  • Dizziness
  • Coldness especially cold hands and feet
  • Shortness of breath
  • Swolen tongue, soreness on your tongue
  • Frequent infections

High iron level symptoms

  • Joint pain
  • Tiredness
  • Weakness
  • Abdominal pain
  • Weight loss
  • Irregular heart rhythm
  • Hair loss
  • Enlarged liver or spleen
  • Bronze-gray skin
  • Low sex drive
  • Depression
  • Impotence

TIBC reference range

TIBC: 250-400 mcg/dL

Iron: 60-170 mcg/dL

Low TIBC causes

  • High iron level
  • Hemochromatosis
  • Hemosiderosis
  • Malnutrition
  • Liver disease
  • Nephrotic syndrome
  • Thalassemia
  • Chronic illness
  • Inflammation
  • Sickle cell anemia
  • Hypoproteinemia

High TIBC causes

  • Iron deficiency
  • Iron deficiency anemia
  • Late pregnancy
  • Birth control pills
  • Acute liver damage
  • Acute or chronic blood loss
  • Increased blood loss with menstruation


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