Hemolysis is the destruction of red blood cells (RBCs). Typically, RBCs can live for up to 120 days before the body naturally destroys them. However, certain conditions and medications may cause them to break down quicker than usual.

RBCs, or erythrocytes, are one of the main components of blood. They have the shape of a slightly indented, flattened disk and help transport oxygen to and from the lungs. The average life span of a healthy RBC is roughly 4 months.

Typically, the body will destroy old or damaged RBCs in the spleen or in other parts of the body through a process known as hemolysis.

Usually, the body is capable of quickly replacing RBCs, producing around 2 million blood cells every second. However, people may experience symptoms of anemia if the body has a low number of RBCs due to excessive hemolysis.

In this article, we discuss hemolysis in detail, including its potential causes and treatment options.

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Hemolysis is the breakdown of RBCs. Some people may also refer to hemolysis by other names, such as hematolysis, erythrolysis, or erythrocytolysis.

Hemolysis is a natural bodily process that occurs when RBCs become too old. As RBCs age, they begin to lose certain properties and work less efficiently. For example, they may lose their deformability, which allows them to reversibly change shape to pass through blood vessels.

As RBCs begin to lose functionality, they accumulate signals that initiate erythrocyte turnover. The body typically performs hemolysis in the spleen. As blood filters through this organ, it is able to detect any old or damaged RBCs. Then, large white blood cells, or macrophages, break down these RBCs.

However, some conditions, medications, and toxins may cause RBCs to break down quicker than usual.

A doctor may measure a person’s hematocrit levels. This refers to the percentage of RBCs in the body. A typical hematocrit level can vary depending on many factors, such as age and race. However, low levels may suggest a high turnover of RBCs.

There are many potential factors that may lead to hemolysis. The cause of hemolysis can be extrinsic, coming from an outside source, or intrinsic, which is when it comes from the RBC itself.


Extrinsic causes include certain conditions or outside factors that destroy RBC, such as:


Certain conditions may result in changes within the RBC itself, which can lead to hemolysis. This can include deformities in the cell structure and metabolism or in the hemoglobin structure.

These conditions may include:

  • hereditary cell membrane conditions, such as hereditary spherocytosis
  • acquired cell membrane conditions, including paroxysmal nocturnal hemoglobinuria
  • conditions affecting RBC metabolism, such as glucose-6-phosphate dehydrogenase deficiency
  • hemoglobinopathies, such as thalassemia and sickle cell disease
  • abnormalities in the RBC membrane, such as elliptocytosis

Excessive hemolysis can lead to hemolytic anemia. This refers to a group of conditions that present with symptoms similar to those of other types of anemia, due to hemolysis occurring too fast or too often.

The condition can develop suddenly or slowly, and it can be mild or severe. Possible symptoms may include:

Symptoms of severe hemolytic anemia may include:

Hemolytic disease of the newborn, which health experts also call erythroblastosis fetalis, is a blood condition in which a rhesus (Rh) factor incompatibility occurs during pregnancy. This refers to a protein that may be present on the surface of RBCs.

If a person with Rh-negative blood becomes pregnant, and the fetus inherits Rh-positive blood from the person’s partner, it can result in a harmful immune response. Around 1–3 in 1,000 people experience this reaction.

During pregnancy, blood from the fetus can cross the placenta and enter the parent’s blood. With Rh incompatibility, the parent’s immune system may recognize this blood as foreign material and produce antibodies against the Rh-positive blood.

This is more likely to occur after the first pregnancy, since the pregnant person’s immune system will recognize the fetus’s blood as foreign and have antibodies ready. If doctors detect this early, they can prevent this condition by giving the parent an Rh immunoglobulin (RHIg) to prevent their immune system from producing antibodies.

A person will receive RHIg as an injection at 28 weeks of pregnancy to prevent the production of antibodies, and within 72 hours of delivering the baby with Rh-positive blood to prevent the production of antibodies that could affect a future pregnancy.

AIHA is a rare condition in children, affecting 0.8 in 100,000 children under the age of 18 years. It can occur after a recent viral infection or after using certain drugs. It can also be due to some conditions.

The most common form of AIHA in children is due to warm-reactive antibodies. The term “warm-reactive” refers to the fact that optimal antigen binding occurs close to body temperature at 98.6ºF.

A 2021 study notes that a sudden presentation of AIHA is often life threatening and progresses quickly, requiring prompt diagnosis, treatment, and monitoring.

Initially, a doctor will review a person’s symptoms and medical history and perform a physical examination.

If they suspect hemolytic anemia, they may request the following tests:

  • Complete blood count: This can help determine the number of RBCs and their size, as well as a person’s hematocrit levels.
  • Peripheral blood smear: This test checks the size and shape of RBCs and identifies any abnormalities.
  • Reticulocyte count: Doctors use this test to check for the ability of the bone marrow to compensate for premature RBC destruction.
  • Serum bilirubin: This yellow pigment is an end product of the breakdown of RBCs. High serum bilirubin levels can indicate hemolytic anemia.
  • Lactic dehydrogenase (LDH): High serum LDH may indicate that RBCs are undergoing hemolysis.
  • Serum haptoglobin: This protein binds to hemoglobin when RBCs die. When too much hemoglobin is in the circulation due to hemolysis, haptoglobin levels will drop.
  • Coombs test: This test helps identify the presence of antibodies that may induce hemolysis.
  • Genetic tests: These tests may help identify hemoglobinopathies, such as sickle cell anemia and thalassemia.

Treatment options will depend on the cause of hemolysis. Moreover, doctors will consider the following when creating a treatment plan:

  • the person’s age and overall health
  • their ability to take and handle treatments
  • severity of the condition

Treatments may include:

  • Blood transfusion: This can help immediately replace RBCs. It also quickly increases a person’s blood cell count.
  • Folic acid: A doctor may suggest this supplement, since hemolysis consumes folate.
  • Corticosteroids: These medications can reduce immune system activity to prevent the body from destroying its own RBCs.
  • Intravenous immunoglobulin (IVIg): A person with certain types of hemolytic anemia may receive IVIg injections to strengthen their immune system. These are injections into a vein and directly into the bloodstream.
  • Rituximab: This is a first-line treatment for steroid refractory warm AIHA. A healthcare professional may also use it as a first- and second-line treatment for cold agglutinin disease.
  • Surgery: In some severe cases, a doctor may suggest removing a person’s spleen through surgery.
  • Hematopoietic stem cell transplant: In some cases, treatment may include bone marrow transplantation to enable an individual’s body to produce sufficient RBCs.

The byproducts of RBC destruction can cause reactions that can damage multiple organs. Complications due to hemolytic anemia can include:

Arrhythmia, cardiomyopathy, heart failure, and iron deficiency are other possible complications.

It is advisable for a person to consult a doctor if they experience any of the following symptoms:

Hemolysis is a natural process where the body destroys older RBCs that no longer work efficiently. However, some conditions, medications, and toxins may cause RBCs to break down prematurely.

When this occurs, people may experience symptoms of anemia, such as fatigue, dizziness, and headaches. In other cases, symptoms can be more severe.

A person exhibiting early signs of anemia should consult a doctor for a prompt diagnosis and treatment.