American Society for Clinical Pathology (ASCP) Technologist in Cytogenetics certification (ASCP CG) Practice Test

When monitoring cell viability in culture, what does a color change to magenta typically indicate?

1. Increased cell growth

2. Cell death due to low CO2

3. Normal cell function

4. Cell death due to high CO2

The correct answer is: Cell death due to low CO2

A color change to magenta in monitoring cell viability usually indicates cellular stress or death due to high CO2 levels. In cell culture, CO2 levels are crucial for maintaining the appropriate pH of the medium. When there is an excess of CO2, it can lead to acidification of the culture medium, affecting cell viability. The color change to magenta suggests that the cells are not thriving under the current conditions, as it is often associated with metabolic distress. In this context, a magenta color is typically seen when a pH indicator in the medium has shifted due to the high CO2, indicating that the cells might be experiencing unfavorable conditions leading to their death. Understanding this relationship between CO2 levels, pH, and cell viability is vital for maintaining healthy cultures and interpreting the results accurately.