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  • Condition in which a person doesn’t have enough red blood cells to carry oxygen throughout the body
  • Symptoms include dizziness, fatigue, and light-headedness
  • Treatments include dietary changes, medication, blood transfusions, and surgery
  • Involves Hematology



Anemia is a condition in which a person doesn’t have enough red blood cells to carry oxygen throughout the body. As a result, they may experience dizziness, fatigue, and light-headedness. There are many potential causes, including nutritional deficiencies, inherited disorders, an underlying medical issue, medication, or an underlying bone marrow disorder (the bone marrow is where the red blood cells are produced).

More than 3 million people in the United States have anemia. The condition can sometimes run in families; it may be a symptom of an inherited condition, such as sickle cell anemia.

Different treatments are available to alleviate symptoms of anemia and increase a person’s levels of healthy red blood cells.

What is anemia?

Anemia is a condition that arises when a person doesn’t have enough red blood cells or does not produce enough hemoglobin, a component of red blood cells. Hemoglobin is a protein that carries oxygen from the lungs to cells throughout the body.

When someone has anemia, there aren’t enough red blood cells to effectively share oxygen with all of the other cells in the body. Because there is a limited supply of oxygenated blood, it is first sent to the essential organs, including the heart, brain, kidney, and liver, to name a few. As a result, areas that are less essential, including the skin, may not receive the proper amount of oxygenated blood. This is why many people with anemia are pale.

Anemia may also impact the spleen. The spleen is a small organ located just above the abdomen that helps the body eliminate red blood cells at the end of their lifespan. When too many red blood cells are destroyed at once (as a result of underlying inherited or autoimmune conditions), the spleen may become enlarged.

What causes anemia?

Below is an explanation of the three ways anemia can develop.

Not enough healthy red blood cells are produced due to:

  • Iron deficiency
  • Vitamin B12 deficiency
  • Folic acid deficiency
  • Certain cancers, including leukemia and lymphoma
  • Cancer treatments
  • Kidney disease
  • Kidney failure
  • Certain medications
  • Alcohol use disorder
  • Lead poisoning
  • Liver disease
  • Thyroid disease
  • Bone marrow disorders

Healthy red blood cells are destroyed before their expected lifespan due to:

  • Sickle cell anemia
  • Thalassemia
  • Immune conditions that destroy red blood cells
  • Liver disease

Blood loss or excessive bleeding due to:

In addition, pregnant women often have mild anemia due to an increase in the volume of the liquid part of their blood (plasma volume).

What are the symptoms of anemia?

Anemia may not always cause symptoms, especially when it is mild. However, when people with anemia experience symptoms, they may notice:

  • Fatigue
  • Weakness
  • Dizziness
  • Lightheadedness
  • Feeling faint
  • Passing out, especially when standing up quickly
  • Quick heartbeat
  • Pale skin
  • Paler-than-usual gums
  • Bruises on the skin
  • Difficulty concentrating
  • Sleep problems
  • Headaches
  • Shortness of breath during physical activity
  • Cold hands and/or feet
  • Chest pain during physical activity
  • Indigestion
  • Nausea

How is anemia diagnosed?

Some people don’t realize they have anemia until routine blood tests call attention to the condition.

But for those who experience symptoms of anemia, doctors may be able to diagnose the condition after asking about their medical history, performing a physical exam, and offering diagnostic tests, most notably blood tests. A CBC (complete blood count) is the test performed most commonly to diagnose anemia.

It’s important to tell your doctor if certain inherited conditions run in your family, including sickle cell anemia and autoimmune diseases, such as lupus or rheumatoid arthritis. You should also discuss your dietary habits, including alcohol intake. For women, it may be important to discuss their menstrual cycle and any pregnancies.

During a physical exam, doctors will check to see if you appear paler than normal. (Gums and inner eyelids may also be checked.) Your heart rate, as well as your breathing, will also be examined. Your doctor may check your abdomen to see if you have an enlarged spleen.

Different tests may be used to diagnose anemia, including:

  • A CBC, which looks at the number of red blood cells, white blood cells, and platelets. It also checks hemoglobin levels and other characteristics of the blood cells.
  • Blood tests, including those that:
    • Measure iron or vitamin B12 and folate levels
    • Check for the presence of immature or abnormal blood cells
    • Check for antibodies that can destroy red blood cells
    • Check to see if there are abnormal hemoglobin or enzymes in the red blood cells
    • Are general tests of your kidney and liver function
    • Check to see if there is inflammation in your body
  • A bone marrow biopsy, which assesses the ability of the bone marrow to produce healthy red blood cells

How is anemia treated?

Different treatments are available for anemia, depending on its cause. Treatments include:

  • Dietary changes/supplements. If your levels of iron, vitamin B12, or folate are low, supplements may be recommended. Some people with vitamin B12 deficiencies may receive vitamin B12 injections. Eating more foods that are rich in iron, vitamin B12, or folate may also be advised. Good choices include beans, dried fruits, eggs, lean red meat, and dark green leafy vegetables for iron; meat, chicken, fish, eggs, and dairy products for vitamin B12; and liver, dark green leafy vegetables, and legumes for folate.
  • Medication. Doctors may prescribe the medication erythropoietin to help stimulate the production of red blood cells in those who produce too few red blood cells.
  • Blood transfusions. When patients lose a significant amount of blood—due to injury, internal bleeding, or heavy menstrual flow—symptoms may improve after a blood transfusion.
  • Surgery. Some people with certain inherited anemia may need to have their spleen removed.

What is the outlook for people with anemia?

For most people, anemia is easy to manage. Dietary changes, medications, and other treatments may make it possible for enough red blood cells to effectively carry oxygen throughout the body, leading to better overall health.

What makes Yale’s approach to treating anemia unique?

“The health care team in Classical Hematology at Yale focuses on the care of patients with non-cancerous blood diseases,” says Yale Medicine hematologist Robert Bona, MD. “One of the more common disorders we care for is anemia due to a variety of causes. As an academic practice at Yale, we strive to deliver the best possible care based on current up-to-date medical information. We also participate in research trials in certain forms of anemia and strive to train the next generation of physicians, physician assistants, and nurses.”