What is the term for the stacking of red blood cells that results in a high erythrocyte sedimentation rate (ESR)?

The term for the stacking of red blood cells that results in a high erythrocyte sedimentation rate (ESR) is known as rouleaux formation. This phenomenon occurs when red blood cells adhere to each other in a stacked formation, resembling a "roll" of coins, due to the presence of certain proteins in the plasma that enhance this aggregation, such as fibrinogen and immunoglobulins.

Rouleaux formation leads to a faster settling of red blood cells in a test tube during the ESR test, which is used as a non-specific marker of inflammation or disease states. Conditions that can lead to increased rouleaux formation include infections, autoimmune diseases, and malignancies, as they often result in elevated levels of acute phase reactants in the blood.

Other processes such as hemolysis refer to the breakdown of red blood cells, which is not related to the sedimentation rate itself. Agglutination typically involves the clumping of cells due to specific antibodies binding to antigens on the surface of red blood cells, which differs from the simple stacking of cells seen in rouleaux. Coagulation refers to the process of blood clotting and does not pertain to the sedimentation of red blood cells. Thus, rouleaux formation is