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 genetics 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.

Research for Your Health

The NHLBI is part of the U.S. Department of Health and Human Services’ National Institutes of Health (NIH)—the Nation’s biomedical research agency that makes important scientific discovery to improve health and save lives. We are committed to advancing science and translating discoveries into clinical practice to promote the prevention and treatment of heart, lung, blood, and sleep disorders including hemolytic anemia. Learn about the current and future NHLBI efforts to improve health through research and scientific discovery.

Improving health with current research
- Hemolytic Anemia

Learn about the following ways the NHLBI continues to translate current research into improved health for people who have hemolytic anemia. Research on this topic is part of the NHLBI’s broader commitment to advancing blood disorders and blood safety through scientific discovery.

  • Program Helps Protect Blood Transfusion Recipients. The NHLBI’s Recipient Epidemiology and Donor Evaluation Study (REDS) program began in 1989 to protect the Nation’s blood supply and improve the benefits and reduce the risks of transfusions. Now in its third phase, called REDS-III, the program supports research in the United States and around the world.
  • Providing Access to NHLBI Biologic Specimens and Data. The Biologic Specimen and Data Repository Information Coordinating Center (BioLINCC) centralizes and integrates biospecimens and clinical data that were once stored in separate repositories. Researchers can find and request available resources on BioLINCC’s secure website, which maximizes the value of these resources and advances heart, lung, blood, and sleep research.
  • New Treatments for Hemolytic Anemia. NHLBI-sponsored clinical trials showed that eculizumab is an effective treatment for a rare and life-threatening type of hemolytic anemia called paroxysmal nocturnal hemoglobinuria (PNH). Eculizumab can reduce or stop the need for blood transfusions. NHLBI research helped eculizumab become the standard treatment for PNH.
  • Supporting Safe Manufacturing of Cell-Based Therapies. The NHLBI’s Production Assistance for Cellular Therapies (PACT) program supports translational research on cellular and genetic therapies by increasing the capacity to manufacture cell products that follow current Good Manufacturing Practices (cGMP) regulations. The PACT program aims to increase the supply and safety of genetically modified cells available for people who have blood disorders such as hemolytic anemia.
  • Accelerating Cures for All People Who Have Sickle Cell Disease. Our Cure Sickle Cell Initiative is a NHLBI-led collaborative research effort to develop genetic therapies for patients who have sickle cell disease. The goal is to have these genetic therapies ready to safely use in clinical research within 5 to 10 years. This patient-focused Initiative will bring together researchers, private sector researchers, patients, providers, advocacy groups, and others as it supports research, education, and community engagement activities.
  • Improving Care for Adolescents and Adults Who Have Sickle Cell Disease. While most U.S. children who have sickle cell disease survive to adulthood, the transition from pediatric to adult care is often challenging. By funding the Sickle Cell Disease Implementation Consortium, we are working to understand current barriers to care, test interventions to overcome those barriers, and develop a new sickle cell disease registry.
  • Network Accelerates Research on Blood and Bone Marrow Transplants. The NHLBI and NCI launched the Blood and Marrow Transplant Clinical Trials Network (BMT CTN) in 2001 to promote large multi-institutional clinical trials that seek to understand the best possible treatment approaches in blood and marrow transplantation. In the United States, about 20,000 patients receive blood or marrow transplants annually.

Advancing research for improved health
- Hemolytic Anemia

In support of our mission, we are committed to advancing hemolytic anemia research in part through the following ways.

  • We perform research. The NHLBI Division of Intramural Research and its Hematology Branch are actively engaged in research on conditions related to hemolytic anemia. Research in the Hematopoiesis and Bone Marrow Failure Laboratory spans the basic sciences, clinical trials, and epidemiology, focusing on blood cell production in healthy individuals and patients who have bone marrow failure.
  • We fund research. The research we fund today will help improve our future health. Our Division of Blood Diseases and Resources is a leader in research on the causes, prevention, and treatment of blood diseases, including hemolytic anemia and sickle cell disease. Search the NIH RePORTer to learn about research the NHLBI is funding on hemolytic anemia.
  • We stimulate high-impact research. The NHLBI Strategic Vision highlights ways we may support research on hemolytic anemia over the next decade.

Learn about exciting research areas the NHLBI is exploring about hemolytic anemia.

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.

Trials at the NIH Clinical Center

Blood disorder research

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 at least 8 years, with or without a blood disorder. This study is located in Bethesda, Maryland.

To learn more about clinical trials at the NIH Clinical Center or to talk to someone about a study that might fit your needs, call the Office of Patient Recruitment 800-411-1222.

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.

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.

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
- Hemolytic Anemia


Image of the cover of the January edition of the Transfusion journal
Credit: Transfusion journal
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