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What happens during hemolysis of red blood cells?

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Blood plasma — blood Blood sediment in test tubes, showing plasma (clear fluid), red blood cells (red), and the release of hemoglobin into the surrounding plasma (pink).

During hemolysis, red blood cells are destroyed, which releases the oxygen-carrying pigment hemoglobin into the surrounding medium.1

This process occurs naturally in a small percentage of cells to remove aged red blood cells from the bloodstream, allowing for the recycling of iron. In the body, this destruction typically takes place in the liver or spleen, specifically within the spleen's red pulp, where hemoglobin is degraded into excretable pigments and iron for reuse.12

While normal, hemolysis can become pathological in conditions like hemolytic anemia, where accelerated cell destruction outpaces the bone marrow's ability to replenish them. This can be caused by intrinsic factors, such as genetic defects, or extrinsic factors, including antibodies, infections, venoms, or physical trauma. Additionally, hemolysis can be induced in laboratory settings using physical agents like heat, freezing, or sound.1