Low iron saturation occurs when the amount of iron in the blood decreases below the recommended range. Measuring transferrin is one way to determine iron saturation.

Iron saturation refers to the amount of iron that is present in the blood. Iron is vital for many molecular processes, including muscle metabolism, oxygen transport, and the maintenance of healthy connective tissue.

People usually obtain sufficient iron from the diet.

However, some individuals may experience low iron, which can lead to iron deficiency anemia. In those with this condition, the blood lacks adequate red blood cells due to a shortage of iron.

This article will explore what constitutes low iron saturation and what symptoms this can produce. It will also explain what may cause low iron saturation, how a medical professional will diagnose it, and what treatments are available.

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A variety of tests measure the level of iron in the blood.

Doctors often test for low iron levels if hemoglobin is low and consistent with anemia.

The normal range of iron saturation can vary from person to person, and it can change over time depending on a person’s health.

There are three measurements that a doctor can take to determine the level of iron in the body.


Transferrin is among the proteins that the blood contains. This protein binds to iron, which it transports around the body and to the bone marrow to produce hemoglobin. Hemoglobin is present in red blood cells.

Measuring transferrin may indicate the level of iron saturation in the blood. The normal range for transferrin is 204–360 milligrams (mg) per deciliter. An amount higher than this indicates a low level of iron saturation.

Total iron-binding capacity (TIBC)

TIBC indicates the total amount of iron to which protein in the blood can bind.

Measuring TIBC may also indicate the saturation level of iron. The normal range for TIBC is 250–450 micrograms per deciliter (mcg/dl). A value higher than this range may indicate iron deficiency or low iron saturation.


A medical professional may also measure the serum iron level.

The serum iron test measures the level of iron in the blood. The normal range for serum iron is:

  • 65–175 mcg/dl for males
  • 50–170 mcg/dl for females
  • 50–120 mcg/dl for children

Values below these reference ranges indicate a low iron saturation.

There are different stages of iron deficiency and iron depletion. These include:

  • Mild deficiency or storage iron depletion: The level of iron and the serum ferritin concentration in the bone marrow decrease.
  • Marginal deficiency or iron deficient erythropoiesis: There is a depletion in the body’s iron stores, and the supply of iron to erythropoietic cells decreases, causing a reduction in transferrin saturation. However, hemoglobin levels may remain within the normal range.
  • Iron deficiency anemia: The exhaustion of iron stores causes hematocrit and hemoglobin levels to decrease. The red blood cells appear small and have low hemoglobin concentrations.

A person with a low iron saturation in the blood may experience various symptoms of iron deficiency. The most common include:

A person may have a low iron saturation level for various reasons.

Common causes of low iron saturation include:

Certain factors can increase a person’s likelihood of experiencing low iron saturation. These include medical conditions and lifestyle choices, such as diet.

Examples of risk factors for low iron saturation include:

  • Age: Infants, young children, pregnant people, and those approaching menopause have an increased risk.
  • Genetics: Certain bleeding disorders, such as Von Willebrand’s disease, affect the blood’s ability to clot.
  • Lifestyle factors: These include eating a vegetarian or vegan diet, eating a diet low in iron-rich foods, and undergoing frequent blood tests or donations.
  • Hormonal changes: People who experience heavy menstruation have a higher risk of becoming anemic. The risk also increases during pregnancy.

A doctor may begin the diagnostic process by carrying out a physical examination and looking for signs of low iron saturation, such as bleeding and spooning of the nails or brittle nails. They may also listen to the heart for any irregular heartbeats and feel the abdomen to check the size of the liver and spleen.

The doctor may then order blood tests to confirm a diagnosis of low iron saturation.

These tests may include:

  • A complete blood count: This blood test reveals the blood cell count, the hemoglobin level, the hematocrit level, and the mean corpuscular volume.
  • Serum iron test: This test measures the amount of iron present in the blood. The level of iron may indicate whether a person has a low iron saturation level.
  • Peripheral smear: This test involves looking at the red blood cells under a microscope to see whether they appear smaller and paler than usual.
  • Transferrin or TIBC test: This test will measure the amount of transferrin in the blood.

The treatment for low iron saturation levels focuses on raising the iron saturation level so that it falls within the normal range.

A person with a low iron saturation level may need to take medicinal iron to increase their saturation level. Medicinal iron contains more iron than multivitamins. Most adults with iron deficiency require 2–5 mg of iron per kilogram of body weight per day.

Experts do not generally recommend iron supplements for people who do not have iron deficiency anemia, as too much iron can damage the organs.

A person can also take other vitamins that improve iron absorption, such as vitamin C.

In cases where the gastrointestinal tract has difficulty absorbing iron, the intravenous delivery of iron — meaning through a blood vessel — may be necessary.

People with severe iron deficiency anemia may require a red blood cell transfusion. This procedure quickly increases the number of red blood cells and iron in the blood and improves iron saturation.

A person can also make lifestyle changes to increase their iron saturation levels. These changes may include:

  • eating a diet rich in iron
  • avoiding certain food items that reduce iron absorption, such as black tea
  • increasing the intake of vitamin C to help the body absorb iron

A low iron saturation level or iron deficiency may lead to other complications. Some of the possible complications include:

  • increased risk of infections
  • heart problems, such as irregular heartbeats or heart murmurs
  • developmental delays in children
  • pregnancy complications, such as preterm delivery or giving birth to an infant with low weight
  • depression

A person can take steps to prevent low iron saturation levels.

For example, they can eat plenty of iron-rich foods, which include:

  • meat and poultry
  • seafood
  • leafy green vegetables, such as broccoli and kale
  • legumes, such as pinto beans and black-eyed peas
  • iron-enriched pasta, grains, rice, and cereals

They can also follow a diet that promotes the absorption of iron in the blood. While vitamin C may increase the bioavailability of iron, experts believe that calcium decreases it.

A person with known risk factors for low iron saturation can reduce their risk by regularly screening for iron deficiency anemia.

Parents and caregivers can help prevent low iron saturation in infants by ensuring that they meet their daily recommended iron intake.

According to the National Institutes of Health (NIH), the recommended iron dietary iron intake is:

  • 11 mg for children aged 7–12 months
  • 7 mg for children aged 1–3 years
  • 10 mg for children aged 4–8 years

Iron-fortified formula can also help a child meet their iron needs. Once a child begins eating solid food, it is important to introduce foods that contain iron.

Iron saturation refers to the amount of iron that is present in the blood. Low iron saturation means that there is a low amount of iron in the blood. Transferrin binds to and transports iron, while ferritin stores this mineral in the body.

Low iron saturation has a range of possible causes, including pregnancy, frequent bleeding, heavy menstruation, and certain genetic or gastrointestinal disorders. A medical professional will diagnose low iron saturation using a combination of tests, which may include a complete blood count, a serum iron test, a transferrin test, and a TIBC test.

The treatment for low iron saturation typically includes a diet rich in iron, iron supplements, and medicinal iron.

Chronic iron deficiency may lead to complications such as heart problems, infections, and developmental delays.

A person can often prevent low iron saturation by following a diet rich in iron to ensure that they meet the recommended daily iron intake.