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

What indicates the appropriate time for a technologist to harvest an in situ amniotic fluid culture?

1. The incubation temperature

2. The number of colonies present

3. The pH level of the culture

4. The time elapsed since inoculation

The correct answer is: The number of colonies present

The appropriate time for a technologist to harvest an in situ amniotic fluid culture is determined by the number of colonies present. In microbiological cultures, the growth of microorganisms is monitored over time, and the appearance of a sufficient number of colonies indicates that the organisms have proliferated adequately. This assessment ensures that the sample is viable and representative of the amniotic fluid environment, which is critical for accurate diagnostic purposes. While the other factors, such as incubation temperature or pH level, can influence the growth and health of the culture, they do not provide as direct or specific guidance for when to harvest in situ cultures. For instance, incubation temperature is essential for maintaining optimal growth conditions, but it does not reflect the growth status of the organisms. Similarly, while pH can affect microbial growth, it is not a definitive measure of whether the culture has reached an appropriate harvest point. The time elapsed since inoculation can indicate growth trends, but without assessing the colony count, it may not accurately inform when to proceed with harvesting the culture. Thus, counting the colonies offers a clear and definitive marker for the readiness of the culture for further evaluation or testing.