The blood smear of a patient shows the following as marked by a black arrow in the picture below.Which among the following best describe the state below?
A. Rouleaux formation.
B. Agglutination of red cells.
C. Both of the above.
D. None of the above.
Ans: A. Rouleaux formation:
- It describes an aggregation of erythrocytes that are aligned one upon the other, resembling stacks of coins.
- The flat surface of the discoid RBCs gives them a large surface area to make contact with and stick to each other; thus forming a rouleau.
- They occur when the plasma protein concentration is high, and because of them the ESR (erythrocyte sedimentation rate) is also increased.
- Acute-phase proteins, particularly fibrinogen, interact with sialic acid on the surface of RBCs to facilitate the formation of rouleaux.
- Conditions which cause rouleaux formation include infections, multiple myeloma, Waldenstrom’s macroglobulinemia, inflammatory and connective tissue disorders, and cancers.
- It also occurs in diabetes mellitus and is one of the causative factors for microvascular occlusion in diabetic retinopathy.
- The observation of red blood cell agglutination (also referred to as autoagglutination) must be distinguished from rouleaux formation .
- Agglutinating red blood cells resemble grapelike clusters whereas red blood cells in rouleaux formation resemble a stack of coins.
- In order to clearly distinguish erythrocyte agglutination from rouleaux formation, a simple saline test can be performed.