| Red blood cell, cell arrangement | Rouleaux formation |
| Definition | Arrangement of > 3 red cells in a linear or branched pattern resembling a stack of coins |
| Ddx | May be seen with poor preparation of the smear or by viewing the thick area of a blood smear |
| Conditions associated with the red cell property | Conditions associated with an inflammatory response and acute phase reaction, multiple myeloma, certain malignant lymphomas |
| Mechanism of formation | Caused by an increase in positively charged proteins, especially fibrinogen and immunoglobulins. The resulting stacking of red cells may lead to an increased erythrocyte sedimentation rate (ESR). |
| Source/author | William Aird |
| Reviewed and edited by | Parul Bhargava |
