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What Causes Hemolytic Anemia?

The immediate cause of hemolytic anemia is the early destruction of red blood cells. This means that red blood cells are destroyed and removed from the bloodstream before their normal lifespan is over.

Many diseases, conditions, and factors can cause the body to destroy its red blood cells. These causes can be inherited or acquired. "Inherited" means your parents passed the gene for the condition on to you. "Acquired" means you aren't born with the condition, but you develop it.

Sometimes, the cause of hemolytic anemia isn't known.

For more information about the specific causes of hemolytic anemia, go to "Types of Hemolytic Anemia."

Inherited Hemolytic Anemias

In inherited hemolytic anemias, the genes that control how red blood cells are made are faulty. You can get a faulty red blood cell gene from one or both of your parents.

Different types of faulty genes cause different types of inherited hemolytic anemia. However, in each type, the body makes abnormal red blood cells. The problem with the red blood cells may involve the hemoglobin, cell membrane, or enzymes that maintain healthy red blood cells.

The abnormal cells may be fragile and break down while moving through the bloodstream. If this happens, an organ called the spleen may remove the cell debris from the bloodstream.

Acquired Hemolytic Anemias

In acquired hemolytic anemias, the body makes normal red blood cells. However, a disease, condition, or other factor destroys the cells. Examples of conditions that can destroy the red blood cells include:

  • Immune disorders
  • Infections
  • Reactions to medicines or blood transfusions
  • Hypersplenism (HI-per-SPLEEN-izm; an enlarged spleen)
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Hemolytic Anemia Clinical Trials

Clinical trials are research studies that explore whether a medical strategy, treatment, or device is safe and effective for humans. To find clinical trials that are currently underway for Hemolytic Anemia, visit

March 21, 2014 Last Updated Icon

The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.