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

Which factors might lead to all cultures failing in a CO2 incubator?

1. Low oxygen levels and humidity

2. High pH and temperature

3. Temperature, CO2 level, and humidity level

4. Contaminants and light exposure

The correct answer is: Temperature, CO2 level, and humidity level

The factors that lead to all cultures failing in a CO2 incubator can primarily be linked to temperature, CO2 level, and humidity level. In a CO2 incubator, maintaining the appropriate temperature is crucial for the growth and survival of cultured cells. Typically, this temperature is around 37 degrees Celsius. Deviations from this optimal temperature can lead to compromised cellular functions and eventually cell death. The CO2 level is also critical, as it is necessary to maintain the pH of the culture medium. A proper CO2 concentration (usually around 5-10%) helps to sustain a balanced pH, which is vital for cell health. If the CO2 levels drop or rise outside the optimal range, it can cause the culture medium to become too basic or too acidic, disrupting cellular processes. Humidity is another vital factor in a CO2 incubator. Low humidity levels can lead to evaporation of culture media, which can alter the concentrations of nutrients and affect cell viability. High humidity, on the other hand, can promote contamination. However, inadequate humidity is more directly linked with the failure of cultures through evaporation and its subsequent impact on the culture medium. Thus, the combination of improper temperature, CO2 concentration, and humidity creates an environment that