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What Is Anemia?

Anemia is when the number of red blood cells in the body gets too low. Red blood cells carry hemoglobin (pronounced: HEE-muh-glow-bin), a protein that carries oxygen throughout the body. Without enough of them, oxygen doesn't get to the body's organs. Without enough oxygen, the organs can't work normally.

There are many different kinds of anemia, so treatments vary.

What Are the Different Kinds of Anemia?

The types of anemia are based on what causes them. They include:

  • Anemias from when red blood cells get broken down too fast, called hemolytic anemias. They include:
    • autoimmune hemolytic anemia: when the body's immune system destroys its own red blood cells
    • inherited hemolytic anemias: these include sickle cell disease, thalassemia, G6PD deficiency, and hereditary spherocytosis
  • Anemia from bleeding. This can happen due to bleeding from an injury, heavy menstrual periods, the gastrointestinal tract, or another medical problem.
  • Anemia from red blood cells being made too slowly, such as:
    • aplastic anemia: when the body stops making red blood cells from an infection, illness, or other cause
    • iron-deficiency anemia: when someone doesn't have enough iron in their diet
    • anemia B12 deficiency: when someone doesn't get enough B12 in the diet or the body can't absorb the B12

Diagram showing a blood vessel with healthy red blood cells (RBCs) and the oxygen and hemoglobin inside each RBC, as described in the article.

What Are the Signs & Symptoms of Anemia?

Some people with anemia don't have any symptoms. Someone who does have symptoms might:

  • look pale
  • seem moody
  • be very tired
  • feel dizzy or lightheaded
  • have a fast heartbeat
  • have jaundice (yellow skin and eyes), an enlarged spleen, and dark tea-colored pee (in hemolytic anemias)

How Is Anemia Diagnosed?

Doctors usually can diagnose anemia by:

  • asking questions about symptoms
  • asking about diet
  • asking if any family members have anemia
  • doing a physical exam
  • doing blood tests to:
    • look at the red blood cells with a microscope to check their size and shape
    • check the amount of hemoglobin and iron in the blood
    • check how fast new RBCs are being made
    • check for any inherited anemias
    • check other cells made in the bone marrow (such as white blood cells)

Sometimes doctors do tests on the bone marrow. The bone marrow is the spongy part inside the bone where blood cells are made. For this test, the doctor puts a needle into the bone to take a small bone marrow sample. The sample is sent to the lab for special tests.

How Is Anemia Treated?

Treatment for anemia depends on the cause. Teens with anemia might need:

  • medicines
  • changes in their diet
  • blood transfusions
  • treatment of another underlying disease
  • to see doctors (hematologists) who specialize in anemia and other blood problems

If you have iron-deficiency anemia, your doctor will probably prescribe an iron supplement to take several times a day. Your doctor may do a follow-up blood test after you've been taking the supplement for a while. Even if the tests show that the anemia has improved, you might have to keep taking iron for several months to build up your body's iron stores.

To make sure you get enough iron, eat a balanced diet every day, starting with a breakfast that includes an iron source, such as an iron-fortified cereal or bread. Lean meat, raisins, chard, eggs, nuts, dried beans, tomato sauce, and molasses also are good sources of iron.

If someone's anemia is caused by another medical condition, doctors will work to treat the cause. People with some types of anemia will need to see a hematologist, who can provide the right medical care for their needs.


Reviewed by: Robin E. Miller, MD
Date Reviewed: 10-06-2019

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