A total iron binding capacity (TIBC) test is a type of blood test that gauges whether there’s too much or too little iron in your bloodstream.

Iron is a type of mineral found in all of the body’s cells. You get the iron you need through your diet. Once iron enters the body, it’s carried throughout your bloodstream by a protein called transferrin, which is produced by your liver. The TIBC test evaluates how well transferrin carries iron through your blood.

In your blood, iron helps form hemoglobin. Hemoglobin is an important protein in red blood cells that helps carry oxygen throughout the body so it can function normally. Iron is considered an essential mineral because hemoglobin can’t be made without it.

Iron can be found in numerous different foods, including:

  • dark green, leafy vegetables, such spinach
  • beans
  • eggs
  • poultry
  • seafood
  • whole grains

The Food and Nutrition Board at the Institute of Medicine recommends people consume certain amounts of iron each day. For healthy people, it recommends the following amounts:

Infants and Children

  • 6 months old or younger: 0.27 milligrams per day (mg/day)
  • 7 months old to age 1: 11 mg/day
  • ages 1 to 3: 7 mg/day
  • ages 4 to 8: 10 mg/day


  • ages 9 to 13: 8 mg/day
  • ages 14 to 18: 11 mg/day
  • ages 19 or older: 8 mg/day


  • ages 9 to 13: 8 mg/day
  • ages 14 to 18: 15 mg/day
  • ages 19 to 50: 18 mg/day
  • ages 51 or older: 8 mg/day
  • lactating women ages 19 to 30 year: 9 mg/day

The Centers for Disease Control and Prevention recommends that pregnant females of all ages take 30 mg/day. Pregnant and lactating women may need different amounts of iron than those recommended. Check with your doctor to find out how much you need.

Doctors typically order TIBC tests to check for medical conditions that cause abnormal iron levels.

Your doctor may perform a TIBC test if you’re experiencing the symptoms of anemia, or a lack of iron in the blood. In the United States, iron is the most common type of dietary deficiency. Iron deficiency is usually the cause of anemia, but the condition may also be triggered by increased blood loss during menstruation, pregnancy, and chronic infections.

The symptoms of low iron levels include:

  • feeling tired and weak
  • skin pallor
  • an increase in infections
  • always feeling cold
  • a swollen tongue
  • difficulty concentrating at school or work
  • delayed mental development in children

A TIBC test may also be ordered if your doctor suspects you have too much iron in your blood. High levels of iron most commonly indicate an underlying medical condition. Some common causes of high iron levels include:

In rare cases, high iron levels may be caused by an overdose of vitamins or iron supplements.

The symptoms of high iron levels include:

  • feeling tired and weak
  • painful joints
  • a change in skin color to bronze or gray
  • abdominal pain
  • sudden weight loss
  • a low sex drive
  • hair loss
  • an irregular heart rhythm

Call your doctor if you’re experiencing the symptoms of low or high iron levels. If any underlying conditions are left untreated, you’re at an increased for serious complications, such as:

  • liver disease
  • a heart attack
  • heart failure
  • diabetes
  • bone problems
  • metabolic issues
  • hormone disorders

Fasting is required for a TIBC test to ensure the most accurate results. This means you shouldn’t eat or drink anything for at least eight hours before the test.

Some medications can also affect the results of a TIBC test, so it’s important to tell your doctor about any prescription or over-the-counter medications you’re taking. Your doctor may tell you to stop taking certain medications before the test. However, you shouldn’t stop taking any medications without talking to your doctor first.

Some medications that can affect the test results include:

  • adrenocorticotropic hormone (ACTH)
  • birth control pills
  • chloramphenicol
  • fluorides

A TIBC test may be ordered along with a serum iron test, which measures the amount of iron in your blood. Together, these tests can help determine whether there’s an abnormal amount of iron in your blood.

The tests involve taking a small sample of blood. Blood is usually drawn from a vein or artery in the hand or the bend of the elbow. The following steps will occur:

  1. A healthcare provider will first clean the area with an antiseptic and then tie an elastic band around your arm. This will make your veins swell with blood.
  2. Once they find a vein, they’ll insert the needle. You can expect to feel a slight prick or stinging sensation when the needle goes in. However, the test itself isn’t painful.
  3. They’ll only collect enough blood as needed to perform the test and any other blood tests your doctor may have ordered.
  4. After enough blood has been drawn, they’ll remove the needle and place a bandage over the puncture site. They’ll tell you to apply pressure to the area with your hand for a few minutes.
  5. The blood sample will then be sent to a laboratory for analysis.
  6. Your doctor will follow up with you to discuss the results.

Blood tests carry few risks. Some people have a slight bruise or experience soreness around the area where the needle was inserted. However, this usually goes away within a few days.

Complications from blood tests are rare, but they can occur. Such complications include:

  • excessive bleeding
  • fainting or dizziness
  • blood accumulating under the skin, or a hematoma
  • infection at the puncture site

Normal values for the TIBC test can vary among laboratories. However, most laboratories define a normal range as 240 to 450 micrograms per deciliter (mcg/dL).

A total iron binding capacity value above 450 mcg/dL usually means that there’s a low level of iron in your blood. This may be caused by a lack of iron in the diet, increased blood loss during menstruation, pregnancy, or a chronic infection.

A total iron binding capacity value below 240 mcg/dL usually means that there’s a high level of iron in your blood. This may be caused by:

  • liver damage
  • iron or lead poisoning
  • frequent blood transfusions
  • hemolytic anemia, which is a condition that causes red blood cells to die prematurely
  • sickle cell anemia, which is an inherited condition that causes red blood cells to change shape
  • hemochromatosis, which is a genetic condition that causes a buildup of iron in the body

Your doctor will explain what your individual results mean for you and what the next steps should be.