What make RBCs settle faster through the plasma when inflammation or infection exist?

a. Bacteria cause red cells to agglutinate and fall faster.
b. Increased number of neutrophils cause red cells to form rouleaux.
c. Inflammation makes the plasma less viscous.
d. Acute phase reactant proteins disrupt the electrical charge that normally separates cells.

ANS: D
When the red cell mass increases, the red cells fall faster through plasma, thus elevating the ESR; rouleaux formation increases the red cell mass. Rouleaux formation occurs when the net negative charge that normally separates red cells from one another is disrupted by acute phase reactant proteins. RBC agglutination also elevates the ESR.