What impact does using a buffer at pH 6.0 have on a Wright's-stained smear?

Using a buffer at pH 6.0 during a Wright's-stained smear can result in red blood cells being stained too pink. This is due to the acid-base balance affecting the staining properties of the sample.

In a Wright's stain, the staining process involves a combination of both eosin and methylene blue dyes, which interact with the components of the cells based on their pH levels. At a lower pH, such as 6.0, eosin (which provides the pink color for red cells) becomes more prominent in its staining action. This leads to an enhanced uptake of the eosin dye by the red blood cells, giving them a more intense pink or reddish appearance than what would typically be observed at the optimal pH, which is around 6.4 to 6.8.

Maintaining the appropriate pH is crucial for accurate cell morphology assessment and diagnostic purposes, as it can influence the visual characteristics of both red and white blood cells in a smear.