Hemolytic Anemia

Hemolytic anemia is a blood disorder that occurs when your red blood cells are destroyed faster than they can be replaced.

Red blood cells develop in the bone marrow, which is the sponge-like tissue inside your bones. Your body normally destroys old or faulty red blood cells in the spleen or other parts of your body through a process called hemolysis. Hemolytic anemia occurs when you have a low number of red blood cells due to too much hemolysis in the body.

There are many types of hemolytic anemia, which doctors diagnose based on the underlying cause of your anemia. Certain conditions can cause hemolysis to happen too fast or too often. Conditions that may lead to hemolytic anemia include inherited blood disorders such as sickle cell disease or thalassemia, autoimmune disorders, bone marrow failure, or infections. Some medicines or side effects to blood transfusions may cause hemolytic anemia.

Hemolytic anemia can develop suddenly or slowly, and it can be mild or severe. Signs and symptoms may include fatigue, dizziness, heart palpitations, pale skin, headache, confusion, jaundice, and a spleen or liver that is larger than normal. Severe hemolytic anemia can cause chills, fever, pain in the back and abdomen, or shock. Severe hemolytic anemia that is not treated or controlled can lead to serious complications, such as irregular heart rhythms called arrhythmias; cardiomyopathy, in which the heart grows larger than normal; or heart failure.

To diagnose hemolytic anemia, your doctor will do a physical exam and order blood tests. Additional tests may include a urine test, a bone marrow test, or genetic tests. People who are diagnosed with mild hemolytic anemia may not need treatment at all. For others, hemolytic anemia can often be treated or controlled. Treatments may include lifestyle changes, medicines, blood transfusions, blood and bone marrow transplants, or surgery to remove the spleen. If your hemolytic anemia is caused by medicines or another health condition, your doctor may change your treatment to control or stop the hemolytic anemia.

Visit Hemolytic Anemia for more information about this topic.

Participate in NHLBI Clinical Trials

We lead or sponsor many studies on different types of hemolytic anemia. See if you or someone you know is eligible to participate in our clinical trials.

Do you have a critically ill child in the ICU?

This study will compare the use of fresh red blood cells and the standard blood bank cells, which are typically older, for blood transfusions in critically ill children in the intensive care unit (ICU). To participate in this study, your child must be between 3 days and 16 years old and require a blood transfusion in the ICU. This study is located at multiple sites across the United States, Canada, and Europe.

Are you considering a blood stem cell transplant?

This study is investigating a new method for collecting blood stem cells from donors to see if it reduces transplant complications, such as rejection, in patients who have blood diseases. To participate in this study, you must have a well-matched donor; you and your donor must be between 4 and 80 years old; and you must not be a candidate for immunosuppressive therapy. This study is located in Bethesda, Maryland.

Are you or your child interested in donating a sample of bone marrow for research?

This study will collect samples of bone marrow from patients who have sickle cell disease or β-thalassemia to help develop genetic therapies. Participants in this study must be 2 years or older and have sickle cell disease or β-thalassemia. You may continue regular treatments while participating in the study. This study is located in Memphis, Tennessee.
View more information about Bone Marrow for Hemoglobinopathy Research.

Have you received a stem cell transplant?

This study aims to monitor the long-term health of patients who have received a donor stem cell transplant from the NIH Clinical Center. To participate in this study, you must be between 10 and 80 years old and had your transplant more than 3 years ago. This study is located in Bethesda, Maryland.

Do you want to take part in blood research?

This study aims to screen patients at the National Institutes of Health Clinical Center who have a blood disorder such as anemia and who may be eligible to participate in studies in the Hematology Branch. It will also determine whether it is safe for you to participate in those studies. Participants in this study must be 2 years or older. This study is located in Bethesda, Maryland.
View more information about Screening for Hematology Branch Protocols.

Would you like to participate in studies on blood disorders?

This study is collecting medical information from health exams and routine tests and procedures to see whether participants may be able to enroll in other studies on blood disorders. Participants in this study must be 8 years or older with or without a blood disorder. This study is located in Bethesda, Maryland.

Are you scheduled for a stem cell transplant with cord blood?

This study will assess the safety and effectiveness of certain cord blood transplants. The study will help researchers learn the best methods for collecting, storing, and using cord blood in transplants. To participate in this study, you must have a disorder that compromises your body’s ability to make blood cells. This study is located in Bethesda, Maryland.
More Information

After reading our Hemolytic Anemia Health Topic, you may be interested in additional information found in the following resources.

Non-NHLBI resources

Image of the cover of the January edition of the Transfusion journal
Credit: Transfusion journal
Research Feature
Every two seconds someone in the United States needs blood. Five million people receive a blood transfusion every year in the U.S. In a country where blood is perennially in short supply, it is the most common medical procedure of all. Yet giving to a blood bank is not always a slam dunk—some people get turned away because of strict rules meant for...