Glacial acetic acid in fixatives causes which effect on red blood cells?

• A. Lysis of red blood cells.
• B. Aggregation of pigments.
• C. Nuclear fragmentation.
• D. Stabilization of membranes.

Answer: (A)

Glacial acetic acid acts as a lysing agent in fixatives, and red blood cells are particularly susceptible to its action. The concentrated acid disrupts membrane lipids and denatures proteins, weakening the delicate erythrocyte membrane and causing the cells to rupture and release their contents. This lysis helps remove blood clutter and can improve visualization of tissue nuclei. It does not cause pigment aggregation, nuclear fragmentation, or membrane stabilization; those effects are not associated with acetic acid in fixatives.