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

What factor significantly impacts the quality of chromosomes viewed under a phase contrast microscope?

1. Type of phase scope used

2. Slide drying after cells have been dropped

3. Time elapsed since sample preparation

4. Sample storage temperature

The correct answer is: Slide drying after cells have been dropped

The quality of chromosomes viewed under a phase contrast microscope is significantly impacted by slide drying after cells have been dropped. Proper slide preparation, specifically the drying time, is crucial for maintaining the structural integrity of the chromosomes. If cells are allowed to dry too quickly or become overly dehydrated, it can lead to distortion or loss of clarity, making it difficult to accurately assess the chromosomal morphology. Furthermore, adequate drying helps in achieving a suitable level of contrast, which is essential when utilizing a phase contrast microscope. When the sample is properly dried, it ensures that the chromosomes are better visualized against the background. This clarity is key for further analysis, such as identifying specific chromosomal abnormalities or structural features. In contrast, factors such as the type of phase scope used, the time elapsed since sample preparation, and sample storage temperature might influence visualization but are not as critical to the immediate quality of the chromosome assessment as the drying process is. While these other factors can impact overall preparation and analysis, it is the slide drying that has the most direct and immediate effect on the visibility of chromosomal characteristics under the microscope.